/* * HP3478A internal USB-GPIB adapter & extension * * DESCRIPTION: * This firmware acts as a bridge between USB-CDC and GPIB while also working * in standalone mode inside HP3478A and MITM-ing GPIB and adding features. * * TODO: * - Implement a VTable for features, to replace the massive switch * to make consistnet entry and exits * - Break main() up into app_process_usb() and app_process_gpib()? * - SCPI-compliant command set for the passthrough mode * - Data logging? */ #include #include #include #include #include #include #include "aht20.h" #include "ch32fun.h" #include "fsusb.h" #include "gpib_defs.h" #include "i2c_bitbang.h" #include "systick.h" #define FW_VERSION "1.1.0" #define MY_ADDR 0 #define DEFAULT_DMM_ADDR 18 // the HP3478A addr #define PIN_VBUS PB10 #define PIN_BUZZ PC13 #define USB_HW_IS_ACTIVE() (!((USBFSCTX.USBFS_DevSleepStatus) & 0x02)) // Timing Config #define USB_DEBOUNCE_CONNECT_MS 50 #define USB_DEBOUNCE_DISCONNECT_MS 200 #define USB_SEND_TIMEOUT_MS 50 #define ENV_SENSOR_READ_INTERVAL_MS 1000 #define DEFAULT_GPIB_TIMEOUT_MS 3000 // Menu Animation Timings #define MENU_DOT_INTERVAL_MS 500 // Speed of "..." addition #define MENU_COMMIT_DELAY_MS 2400 // Time to hold before entering mode #define MENU_SUBLAYER_DELAY_MS 500 // Time to "hover" before dots start #define MENU_DEBOUNCE_MS 200 // Button press dead-time #define MENU_LOCKOUT_MS 1000 // How long to ignore SRQ for after exiting menu // Polling #define POLL_INTERVAL_MS 100 // 10Hz polling when in Passthrough #define DMM_RECOVERY_DELAY_MS 1000 // Backoff if DMM vanishes // Diode sound #define DIODE_TH_SHORT 0.050 // Volts (below this = SHORT) #define DIODE_TH_OPEN 2.500 // Volts (above this = OPEN/OL) #define DIODE_STABLE_MS 20 // wait X ms for voltage to settle #define DIODE_CHIRP_MS 50 // PT1000 (DIN 43760 / IEC 751 Standard) #define RTD_A 3.9083e-3 #define RTD_B -5.775e-7 #define RTD_R0 1000.0 // Thermocouple #define CJC_FALLBACK_TEMP 22.0 // used if !app.env_sensor_present // this is just cursed but.. yeah, the PCB is near a transformer // ideally, the temp should be measured right at the binding posts.. #define CJC_SELF_HEATING_OFFSET 4.0 #define TYPE_K_SCALE 24390.24 // 1 / 41uV // dBm #define DBM_REF_Z 50.0 // Stats #define STATS_CYCLE_TIME_MS 3000 // time per screen (Live -> Avg -> Min...) #define STATS_INIT_MIN_VAL 1.0e9 #define STATS_INIT_MAX_VAL -1.0e9 // HP3478A #define HP_DISP_LEN 12 // 12 chars // max str length required to fill 12 segments. // Worst case: 12 chars + 12 dots/commas + 1 Null terminator = 25 bytes #define HP_DISP_BUF_SIZE ((HP_DISP_LEN * 2) + 1) #define CONT_THRESHOLD_OHMS 10.0 // continuity beep threshold #define CONT_DISP_UPDATE_MS 250 // display throttling #define DMM_OL_THRESHOLD 9.0e9 // HP sends +9.9999E+9 on overload #define DMM_OL_NEG_THRESHOLD -9.0e9 #define REL_STABLE_SAMPLES 3 // filter depth for Relative NULL typedef enum { CMD_UNKNOWN = 0, // Prologix / Standard GPIB CMD_ADDR, CMD_AUTO, CMD_READ, CMD_WRITE, CMD_TRG, CMD_CLR, CMD_DCL, CMD_SPOLL, CMD_LOC, CMD_GTL, CMD_LLO, CMD_REN, CMD_IFC, CMD_STAT, CMD_RST, CMD_VER, CMD_HELP, // HP3478A Features CMD_CONT, CMD_TEMP, CMD_REL, CMD_XOHM, CMD_DBM, CMD_DIODE, CMD_MATH, CMD_NORM, CMD_DISP, CMD_ENV, CMD_TIMEOUT } cmd_id_t; typedef struct { const char* name; cmd_id_t id; } cmd_entry_t; static const cmd_entry_t COMMAND_TABLE[] = { // common {"read", CMD_READ}, {"write", CMD_WRITE}, {"addr", CMD_ADDR}, {"trg", CMD_TRG}, {"auto", CMD_AUTO}, {"stat", CMD_STAT}, // feats {"cont", CMD_CONT}, {"temp", CMD_TEMP}, {"rel", CMD_REL}, {"xohm", CMD_XOHM}, {"dbm", CMD_DBM}, {"diode", CMD_DIODE}, {"math", CMD_MATH}, {"norm", CMD_NORM}, {"disp", CMD_DISP}, {"env", CMD_ENV}, // GPIB mgmt {"read_tmo_ms", CMD_TIMEOUT}, {"tmo", CMD_TIMEOUT}, {"clr", CMD_CLR}, {"dcl", CMD_DCL}, {"spoll", CMD_SPOLL}, {"loc", CMD_LOC}, {"gtl", CMD_GTL}, {"llo", CMD_LLO}, {"ren", CMD_REN}, {"ifc", CMD_IFC}, {"rst", CMD_RST}, {"ver", CMD_VER}, {"help", CMD_HELP}, {"?", CMD_HELP}, {NULL, CMD_UNKNOWN}}; typedef enum { MODE_PASSTHROUGH = 0, // Standard USB-GPIB bridge MODE_MENU, // User is cycling options on DMM display MODE_FEAT_REL, // Relative Mode active MODE_FEAT_TEMP, // PT1000 Temp Mode active MODE_FEAT_DBM, // Power ratio using a 50R impedance as ref MODE_FEAT_CONT, // Continuity Mode active MODE_FEAT_DIODE, // Diode test mode MODE_FEAT_XOHM, // Extended Ohms active MODE_FEAT_STATS // avg/min/max } work_mode_t; typedef enum { MENU_REL = 0, MENU_TEMP, MENU_DBM, MENU_CONT, MENU_DIODE, MENU_XOHM, MENU_STATS, MENU_EXIT, MENU_MAX_ITEMS } menu_item_t; typedef enum { // Generic NTC_10K_3950 = 0, // Generic china 3950 NTC_10K_3435, // alt 10k NTC_50K_3950, // alt 50k NTC_100K_3950, // alt 100k // YSI 44000 NTC_YSI_2252, // YSI 44004 (Mix B) NTC_YSI_3K, // YSI 44005 (Mix B) NTC_YSI_5K, // YSI 44007 (Mix B) NTC_YSI_10K_A, // YSI 44006 (Mix H) NTC_YSI_10K_B, // YSI 44016 (Mix B) NTC_YSI_30K, // YSI 44008 (Mix H) NTC_YSI_100K, // YSI 44011 (Mix H) NTC_YSI_1MEG, // YSI 44015 (Mix H) NTC_MAX_ITEMS } ntc_preset_t; typedef struct { double r0; // R @ 25C double beta; // beta coefficient (typ. 3000-4500) const char* name; // display name } ntc_def_t; // UI Strings static const char* MENU_NAMES[] = {"REL", "TEMP", "DBM", "CONT", "DIODE", "XOHM", "STATS", "EXIT"}; static const char* SENSOR_NAMES[] = {"PT1000", "THERM", "TYPE K"}; static const char* WIRE_NAMES[] = {"2-WIRE", "4-WIRE"}; // some common NTC defs static const ntc_def_t NTC_DEFS[] = { // Generic/China {10000.0, 3950.0, "10K 3950"}, // black bead) {10000.0, 3435.0, "10K 3435"}, // euro? {50000.0, 3950.0, "50K 3950"}, // generic {100000.0, 3950.0, "100K 3950"}, // generic // From YSI datasheet {2252.0, 3891.0, "2.252K YSI"}, // 44004 {3000.0, 3891.0, "3K YSI"}, // 44005 {5000.0, 3891.0, "5K YSI"}, // 44007 {10000.0, 3574.0, "10K YSI A"}, // Mix H (YSI 10k) {10000.0, 3891.0, "10K YSI B"}, // Mix B (matches 2.2K curve) {30000.0, 3810.0, "30K YSI"}, // 44008 {100000.0, 3988.0, "100K YSI"}, // 44011 {1000000.0, 4582.0, "1MEG YSI"} // 44015 }; // Sub-menu states typedef enum { SUBMENU_NONE = 0, SUBMENU_TEMP_SENS, // step 1: sensor Type SUBMENU_TEMP_WIRE, // step 2a: wire mode (skipped for Type K) SUBMENU_TEMP_NTC // step 2b: NTC Value (Thermistor only) } submenu_state_t; // Sensor Types typedef enum { SENS_PT1000 = 0, SENS_THERMISTOR, SENS_TYPE_K, SENS_MAX_ITEMS } temp_sensor_t; typedef enum { WIRE_2W = 0, WIRE_4W, WIRE_MAX_ITEMS } wire_mode_t; typedef enum { DIODE_STATE_OPEN = 0, // probes open DIODE_STATE_CHECKING, // voltage @ diode range, checking stability DIODE_STATE_SHORT, // voltage too low, silent DIODE_STATE_DONE // chirped, latched silent } diode_state_t; typedef struct { const char* cmd_func; const char* cmd_range; const char* cmd_digits; const char* cmd_az; char unit_str[5]; // "VDC", "OHM", etc. } dmm_decoded_state_t; typedef union { struct { double offset; uint8_t stable_count; char unit[5]; } rel; struct { double min; double max; double sum; uint32_t count; uint32_t disp_timer; uint8_t view_mode; char unit[5]; } stats; struct { double r1; uint8_t calibrated; } xohm; struct { uint8_t connected; // touchy? uint32_t chirp_start; // when we began the touchy } diode; struct { // we're using very fast ADC mode for cont, so throttle disp update // although.. ideally this should be done globally somehow uint32_t last_disp_update; } cont; // menu state (only used when in MODE_MENU) struct { uint32_t timer; uint8_t layer; // submenu_state_t uint8_t sub_pos; // position in submenu } menu; } mode_data_t; typedef struct { // Hardware State Flags uint8_t usb_online : 1; uint8_t usb_raw_prev : 1; uint8_t env_sensor_present : 1; uint8_t auto_read : 1; uint8_t dmm_online : 1; uint8_t has_saved_state : 1; uint8_t beep_active : 1; uint8_t reserved : 1; // Addresses uint8_t target_addr; uint8_t dmm_addr; uint32_t gpib_timeout_ms; // Timers uint32_t usb_ts; uint32_t env_last_read; uint32_t last_poll_time; uint32_t poll_interval; uint32_t ignore_input_start_ts; uint32_t beep_start_ts; // buzzer uint32_t beep_duration; // Logic work_mode_t current_mode; int menu_pos; // high-level menu position (REL, TEMP etc.) // Config Selection temp_sensor_t temp_sensor; wire_mode_t temp_wire_mode; ntc_preset_t temp_ntc_preset; // Environmental Data aht20_data current_env; // DMM Restore uint8_t saved_state_bytes[5]; // Display shadow buffer (cache) char last_disp_sent[HP_DISP_BUF_SIZE]; // Unionized Mode Data mode_data_t data; } app_state_t; static app_state_t app = {.dmm_addr = DEFAULT_DMM_ADDR, .target_addr = DEFAULT_DMM_ADDR, .poll_interval = POLL_INTERVAL_MS, .gpib_timeout_ms = DEFAULT_GPIB_TIMEOUT_MS}; typedef union { // MODE A: Command Processing Context // Used when we are inside process_command() struct { char line_buf[128]; // Replaces: scratch.cmd.line_buf char fmt_buf[128]; // Replaces: scratch.cmd.fmt_buf (For "Stat:", "OK", // etc.) } cmd; // MODE B: General IO Context // Used when reading from GPIB or calculating Features struct { // Replaces: scratch.io.raw_data // Used for reading GPIB data ("+1.234E-3") before parsing char raw_data[256]; } io; // MODE C: Display Context // Used when formatting text for the HP3478A struct { // Replaces: scratch.disp.full_cmd AND scratch.disp.full_cmd // We will generate the final command directly here char full_cmd[64]; } disp; uint8_t raw[256]; } app_scratchpad_t; static app_scratchpad_t scratch; // USB Ring Buffer #define USB_RX_BUF_SIZE 512 volatile uint8_t usb_rx_buffer[USB_RX_BUF_SIZE]; volatile uint16_t usb_rx_head = 0; volatile uint16_t usb_rx_tail = 0; static uint8_t cdc_line_coding[7] = {0x00, 0xC2, 0x01, 0x00, 0x00, 0x00, 0x08}; volatile uint8_t buzzer_active = 0; static uint32_t current_buzz_freq = 0; extern volatile uint8_t usb_debug; // helpers static int starts_with_nocase(const char* str, const char* prefix) { while (*prefix) { if (tolower((unsigned char)*str) != tolower((unsigned char)*prefix)) { return 0; } str++; prefix++; } return 1; } static char* skip_spaces(char* str) { while (*str && isspace((unsigned char)*str)) { str++; } return str; } static cmd_id_t parse_command_id(const char* cmd) { for (int i = 0; COMMAND_TABLE[i].name != NULL; i++) { if (starts_with_nocase(cmd, COMMAND_TABLE[i].name)) { int len = strlen(COMMAND_TABLE[i].name); char next = cmd[len]; if (next == 0 || isspace((unsigned char)next)) { return COMMAND_TABLE[i].id; } } } return CMD_UNKNOWN; } void double_to_str(char* buf, size_t buf_size, double val, int prec) { if (buf_size == 0) return; buf[0] = '\0'; size_t offset = 0; // NaN/Inf if (val != val) { if (buf_size > 3) strcpy(buf, "NAN"); return; } // negative if (val < 0.0) { if (offset < buf_size - 1) buf[offset++] = '-'; val = -val; } // multiplier if (prec < 0) prec = 0; if (prec > 9) prec = 9; // limit precision unsigned long long multiplier = 1; for (int i = 0; i < prec; i++) multiplier *= 10; // scale and round val = (val * (double)multiplier) + 0.5; // split integer and fractional parts unsigned long long full_scaled = (unsigned long long)val; unsigned long int_part = (unsigned long)(full_scaled / multiplier); unsigned long long frac_part = full_scaled % multiplier; // print integer part int res = snprintf(buf + offset, buf_size - offset, "%lu", int_part); if (res < 0 || (size_t)res >= buf_size - offset) { buf[buf_size - 1] = '\0'; return; } offset += (size_t)res; // print decimal point and fraction if (prec > 0 && offset < buf_size - 1) { buf[offset++] = '.'; unsigned long long divider = multiplier / 10; while (divider > 0 && offset < buf_size - 1) { unsigned int digit = (unsigned int)(frac_part / divider); buf[offset++] = (char)('0' + digit); frac_part %= divider; divider /= 10; } } buf[offset] = '\0'; } // "Note that period, comma, and semicolon go between characters" int count_non_visual_chars(const char* s) { int c = 0; while (*s) { if (*s == '.' || *s == ',' || *s == ';') c++; s++; } return c; } void format_metric_value(char* buffer, size_t buf_len, double val, const char* unit, int auto_scale) { // must hold 12 visible chars + 1 null. if (buf_len <= HP_DISP_LEN) return; memset(buffer, ' ', HP_DISP_LEN); buffer[HP_DISP_LEN] = '\0'; // scale double scaled = val; double abs_val = fabs(val); char suffix = 0; if (auto_scale) { if (abs_val >= 1.0e9) { scaled *= 1.0e-9; suffix = 'G'; } else if (abs_val >= 1.0e6) { scaled *= 1.0e-6; suffix = 'M'; } else if (abs_val >= 1.0e3) { scaled *= 1.0e-3; suffix = 'K'; } } double abs_s = fabs(scaled); // unit + suffix size_t unit_len = strlen(unit); size_t suffix_len = (suffix != 0) ? 1 : 0; size_t meta_vis_len = unit_len + suffix_len; if (meta_vis_len > (HP_DISP_LEN - 3)) { // truncate unit? } int int_digits = 1; if (abs_s >= 1.0) { double t = abs_s; while (t >= 10.0) { t /= 10.0; int_digits++; } } int is_neg = (scaled < 0.0); // visual slots needed for non-decimal part (sign + ints + space separator) int separator = (meta_vis_len > 0) ? 1 : 0; int reserved_vis = is_neg + int_digits + separator + meta_vis_len; // calculate allowed decimals (visual) int allowed_prec = HP_DISP_LEN - reserved_vis; if (allowed_prec < 0) allowed_prec = 0; int desired_prec = 5; if (abs_s >= 10000.0) desired_prec = 1; else if (abs_s >= 1000.0) desired_prec = 2; else if (abs_s >= 100.0) desired_prec = 3; else if (abs_s >= 10.0) desired_prec = 4; int final_prec = (desired_prec < allowed_prec) ? desired_prec : allowed_prec; // render num char num_buf[32]; double_to_str(num_buf, sizeof(num_buf), scaled, final_prec); // calc padding int num_bytes = strlen(num_buf); int num_dots = count_non_visual_chars(num_buf); int num_vis_len = num_bytes - num_dots; // total visual slots used so far int total_vis_used = num_vis_len + meta_vis_len; // to push unit to the right edge int spaces_needed = HP_DISP_LEN - total_vis_used; if (spaces_needed < 1 && meta_vis_len > 0) spaces_needed = 1; // enforce 1 space if possible? if (total_vis_used + spaces_needed > HP_DISP_LEN) { // crunch: if overflow (very large number), reduce spaces spaces_needed = HP_DISP_LEN - total_vis_used; if (spaces_needed < 0) spaces_needed = 0; } // [number] [spaces] [suffix] [unit] // num strcpy(buffer, num_buf); // spaces int current_len = strlen(buffer); for (int i = 0; i < spaces_needed; i++) { buffer[current_len++] = ' '; } buffer[current_len] = '\0'; // suffix if (suffix) { buffer[current_len++] = suffix; buffer[current_len] = '\0'; } // unit if (unit_len > 0) { strcat(buffer, unit); } } double parse_double(const char* s) { double mantissa = 0.0; int exponent = 0; int sign = 1; int decimal_seen = 0; int decimal_counts = 0; // skip whitespace while (*s == ' ') s++; // handle sign if (*s == '+') { s++; } else if (*s == '-') { sign = -1; s++; } // parse Mantissa as pure int while (*s) { if (*s >= '0' && *s <= '9') { mantissa = (mantissa * 10.0) + (*s - '0'); if (decimal_seen) { decimal_counts++; } } else if (*s == '.') { decimal_seen = 1; } else if (*s == 'E' || *s == 'e') { s++; exponent = atoi(s); break; } else { break; } s++; } exponent -= decimal_counts; double power = 1.0; int e_abs = abs(exponent); while (e_abs-- > 0) power *= 10.0; if (exponent > 0) { mantissa *= power; } else { mantissa /= power; } return mantissa * sign; } void decode_dmm_state_bytes(const uint8_t* state_bytes, dmm_decoded_state_t* out) { uint8_t b1 = state_bytes[0]; uint8_t b2 = state_bytes[1]; // decode function & unit switch ((b1 >> 5) & 0x07) { case 2: out->cmd_func = HP3478A_FUNC_AC_VOLTS; strcpy(out->unit_str, "VAC"); break; case 3: out->cmd_func = HP3478A_FUNC_OHMS_2WIRE; strcpy(out->unit_str, "OHM"); break; case 4: out->cmd_func = HP3478A_FUNC_OHMS_4WIRE; strcpy(out->unit_str, "OHM"); break; case 5: out->cmd_func = HP3478A_FUNC_DC_CURRENT; strcpy(out->unit_str, "ADC"); break; case 6: out->cmd_func = HP3478A_FUNC_AC_CURRENT; strcpy(out->unit_str, "AAC"); break; case 7: out->cmd_func = HP3478A_FUNC_OHMS_EXT; strcpy(out->unit_str, "OHM"); break; default: // case 1 or anything else out->cmd_func = HP3478A_FUNC_DC_VOLTS; strcpy(out->unit_str, "VDC"); break; } // decode range (bits 4-2) + autorange (byte 2 bit 1) if (b2 & 0x02) { out->cmd_range = HP3478A_RANGE_AUTO; } else { switch ((b1 >> 2) & 0x07) { case 1: out->cmd_range = HP3478A_RANGE_NEG_2; break; case 2: out->cmd_range = HP3478A_RANGE_NEG_1; break; case 3: out->cmd_range = HP3478A_RANGE_0; break; case 4: out->cmd_range = HP3478A_RANGE_1; break; case 5: out->cmd_range = HP3478A_RANGE_2; break; case 6: out->cmd_range = HP3478A_RANGE_3; break; case 7: out->cmd_range = HP3478A_RANGE_4; break; default: out->cmd_range = HP3478A_RANGE_0; break; } } // decode digits (bits 1-0) switch (b1 & 0x03) { case 2: out->cmd_digits = HP3478A_DIGITS_4_5; break; case 3: out->cmd_digits = HP3478A_DIGITS_3_5; break; default: out->cmd_digits = HP3478A_DIGITS_5_5; break; } // decode autozero (byte 2 bit 2) out->cmd_az = (b2 & 0x04) ? HP3478A_AUTOZERO_ON : HP3478A_AUTOZERO_OFF; } // constructs the base configuration string (F R N Z) from decoded state void build_restoration_string(char* buffer, const dmm_decoded_state_t* state) { strcpy(buffer, HP3478A_DISP_NORMAL); strcat(buffer, state->cmd_func); strcat(buffer, state->cmd_range); strcat(buffer, state->cmd_digits); strcat(buffer, state->cmd_az); } #ifdef GPIB_DEBUG static void gpib_dump_state(const char* context) { uint8_t d = 0; if (!GPIB_READ(PIN_DIO1)) d |= 0x01; if (!GPIB_READ(PIN_DIO2)) d |= 0x02; if (!GPIB_READ(PIN_DIO3)) d |= 0x04; if (!GPIB_READ(PIN_DIO4)) d |= 0x08; if (!GPIB_READ(PIN_DIO5)) d |= 0x10; if (!GPIB_READ(PIN_DIO6)) d |= 0x20; if (!GPIB_READ(PIN_DIO7)) d |= 0x40; if (!GPIB_READ(PIN_DIO8)) d |= 0x80; printf("\n[GPIB DUMP] %s\n", context); printf(" M: ATN=%d IFC=%d REN=%d EOI=%d | S: SRQ=%d\n", GPIB_READ(PIN_ATN), GPIB_READ(PIN_IFC), GPIB_READ(PIN_REN), GPIB_READ(PIN_EOI), GPIB_READ(PIN_SRQ)); printf(" H: DAV=%d NRFD=%d NDAC=%d\n", GPIB_READ(PIN_DAV), GPIB_READ(PIN_NRFD), GPIB_READ(PIN_NDAC)); printf(" D: 0x%02X\n", d); } #else #define gpib_dump_state(x) ((void)0) #endif // low level void gpib_write_data(uint8_t b) { uint32_t bshr = 0; if (b & 0x01) bshr |= (MASK_DIO1 << 16); else bshr |= MASK_DIO1; if (b & 0x02) bshr |= (MASK_DIO2 << 16); else bshr |= MASK_DIO2; if (b & 0x04) bshr |= (MASK_DIO3 << 16); else bshr |= MASK_DIO3; if (b & 0x08) bshr |= (MASK_DIO4 << 16); else bshr |= MASK_DIO4; if (b & 0x10) bshr |= (MASK_DIO5 << 16); else bshr |= MASK_DIO5; if (b & 0x20) bshr |= (MASK_DIO6 << 16); else bshr |= MASK_DIO6; if (b & 0x40) bshr |= (MASK_DIO7 << 16); else bshr |= MASK_DIO7; if (b & 0x80) bshr |= (MASK_DIO8 << 16); else bshr |= MASK_DIO8; GPIOB->BSHR = bshr; } uint8_t gpib_read_data(void) { uint32_t r = ~(GPIOB->INDR); // active low uint8_t b = 0; if (r & MASK_DIO1) b |= 0x01; if (r & MASK_DIO2) b |= 0x02; if (r & MASK_DIO3) b |= 0x04; if (r & MASK_DIO4) b |= 0x08; if (r & MASK_DIO5) b |= 0x10; if (r & MASK_DIO6) b |= 0x20; if (r & MASK_DIO7) b |= 0x40; if (r & MASK_DIO8) b |= 0x80; return b; } static int gpib_wait_pin(int pin, int expected_state) { uint32_t start = millis(); while (GPIB_READ(pin) != expected_state) { if ((millis() - start) > app.gpib_timeout_ms) { #ifdef GPIB_DEBUG // Print which specific pin failed char* pin_name = "UNKNOWN"; if (pin == PIN_NRFD) pin_name = "NRFD"; else if (pin == PIN_NDAC) pin_name = "NDAC"; else if (pin == PIN_DAV) pin_name = "DAV"; printf("[GPIB ERR] Timeout waiting for %s to be %d\n", pin_name, expected_state); gpib_dump_state("TIMEOUT STATE"); #endif return -1; } } return 0; } int gpib_write_byte(uint8_t data, int assert_eoi) { #ifdef GPIB_DEBUG printf("[TX] 0x%02X (EOI=%d)... ", data, assert_eoi); #endif // wait for listeners to be ready if (gpib_wait_pin(PIN_NRFD, 1) < 0) { return -1; } gpib_write_data(data); // assert EOI if this is the last byte if (assert_eoi) { GPIB_ASSERT(PIN_EOI); } Delay_Us(1); // T1 GPIB_ASSERT(PIN_DAV); // wait for listeners ack if (gpib_wait_pin(PIN_NDAC, 1) < 0) { GPIB_RELEASE(PIN_DAV); GPIB_RELEASE(PIN_EOI); #ifdef GPIB_DEBUG printf("NDAC stuck LOW, (device didn't accept)\n"); #endif return -2; } GPIB_RELEASE(PIN_DAV); GPIB_RELEASE(PIN_EOI); // float bus gpib_write_data(0x00); return 0; } int gpib_read_byte(uint8_t* data, int* eoi_asserted) { // sssert busy state GPIB_ASSERT(PIN_NDAC); // not accepted yet GPIB_ASSERT(PIN_NRFD); // not ready yet // float data lines gpib_write_data(0x00); // Delay_Us(2); // signal ready for data GPIB_RELEASE(PIN_NRFD); // wait for talker to assert DAV if (gpib_wait_pin(PIN_DAV, 0) < 0) { GPIB_RELEASE(PIN_NDAC); GPIB_RELEASE(PIN_NRFD); return -1; // timeout } Delay_Us(1); // T2 // read data and EOI status *data = gpib_read_data(); *eoi_asserted = (GPIB_READ(PIN_EOI) == 0); // active LOW // signal not ready (processing data) GPIB_ASSERT(PIN_NRFD); // signal data accepted GPIB_RELEASE(PIN_NDAC); // wait for talker to release DAV if (gpib_wait_pin(PIN_DAV, 1) < 0) { GPIB_RELEASE(PIN_NRFD); return -2; // timeout } // prepare for next byte GPIB_ASSERT(PIN_NDAC); return 0; } typedef enum { SESSION_WRITE, SESSION_READ } session_mode_t; // Sets up Talker/Listener for data transfer int gpib_start_session(uint8_t target_addr, session_mode_t mode) { GPIB_ASSERT(PIN_ATN); Delay_Us(20); // Unlisten everyone first to clear bus state if (gpib_write_byte(GPIB_CMD_UNL, 0) < 0) { GPIB_RELEASE(PIN_ATN); return -1; } uint8_t talker = (mode == SESSION_WRITE) ? MY_ADDR : target_addr; uint8_t listener = (mode == SESSION_WRITE) ? target_addr : MY_ADDR; // Untalk, Set Talker, Set Listener if (gpib_write_byte(GPIB_CMD_UNT, 0) < 0) goto err; if (gpib_write_byte(GPIB_CMD_TAD | talker, 0) < 0) goto err; if (gpib_write_byte(GPIB_CMD_LAD | listener, 0) < 0) goto err; Delay_Us(10); GPIB_RELEASE(PIN_ATN); // Switch to Data Mode Delay_Us(10); return 0; err: GPIB_RELEASE(PIN_ATN); return -1; } // Bus management // Assert Interface Clear (IFC) void gpib_interface_clear(void) { GPIB_ASSERT(PIN_IFC); Delay_Ms(1); // IEEE-488 requires >100us GPIB_RELEASE(PIN_IFC); Delay_Ms(1); } // Control Remote Enable (REN) void gpib_remote_enable(int enable) { if (enable) { GPIB_ASSERT(PIN_REN); } else { GPIB_RELEASE(PIN_REN); } } // Check SRQ Line (Active Low) int gpib_check_srq(void) { return !GPIB_READ(PIN_SRQ); } // Universal Commands (Affects All Devices) // Universal Device Clear (DCL) // Resets logic of ALL devices on the bus int gpib_universal_clear(void) { GPIB_ASSERT(PIN_ATN); Delay_Us(20); if (gpib_write_byte(GPIB_CMD_DCL, 0) < 0) { GPIB_RELEASE(PIN_ATN); return -1; } Delay_Us(10); GPIB_RELEASE(PIN_ATN); return 0; } // Local Lockout (LLO) // Disables front panel "Local" buttons on all devices int gpib_local_lockout(void) { GPIB_ASSERT(PIN_ATN); Delay_Us(20); // LLO is universal, no addressing needed if (gpib_write_byte(GPIB_CMD_LLO, 0) < 0) { GPIB_RELEASE(PIN_ATN); return -1; } Delay_Us(10); GPIB_RELEASE(PIN_ATN); return 0; } // Addressed cmds // Selected Device Clear (SDC) // Resets logic of ONLY the targeted device int gpib_device_clear(uint8_t addr) { GPIB_ASSERT(PIN_ATN); Delay_Us(20); if (gpib_write_byte(GPIB_CMD_UNL, 0) < 0) goto err; if (gpib_write_byte(GPIB_CMD_LAD | addr, 0) < 0) goto err; if (gpib_write_byte(GPIB_CMD_SDC, 0) < 0) goto err; GPIB_RELEASE(PIN_ATN); return 0; err: GPIB_RELEASE(PIN_ATN); return -1; } // Group Execute Trigger (GET) // Triggers the device to take a measurement int gpib_trigger(uint8_t addr) { GPIB_ASSERT(PIN_ATN); Delay_Us(20); if (gpib_write_byte(GPIB_CMD_UNL, 0) < 0) goto err; if (gpib_write_byte(GPIB_CMD_LAD | addr, 0) < 0) goto err; if (gpib_write_byte(GPIB_CMD_GET, 0) < 0) goto err; GPIB_RELEASE(PIN_ATN); return 0; err: GPIB_RELEASE(PIN_ATN); return -1; } // Go To Local (GTL) // Addresses a specific device and restores Front Panel control // (Keeps REN asserted for other devices on the bus) int gpib_go_to_local(uint8_t addr) { GPIB_ASSERT(PIN_ATN); Delay_Us(20); if (gpib_write_byte(GPIB_CMD_UNL, 0) < 0) goto err; if (gpib_write_byte(GPIB_CMD_LAD | addr, 0) < 0) goto err; if (gpib_write_byte(GPIB_CMD_GTL, 0) < 0) goto err; GPIB_RELEASE(PIN_ATN); return 0; err: GPIB_RELEASE(PIN_ATN); return -1; } // Serial Poll // Reads the Status Byte (STB) from the device int gpib_serial_poll(uint8_t addr, uint8_t* status) { GPIB_ASSERT(PIN_ATN); Delay_Us(20); // setupo seq: UNL -> SPE -> LAD(Me) -> TAD(Target) if (gpib_write_byte(GPIB_CMD_UNL, 0) < 0) goto err; if (gpib_write_byte(GPIB_CMD_SPE, 0) < 0) goto err; if (gpib_write_byte(GPIB_CMD_LAD | MY_ADDR, 0) < 0) goto err; if (gpib_write_byte(GPIB_CMD_TAD | addr, 0) < 0) goto err; // drop ATN to read data GPIB_RELEASE(PIN_ATN); Delay_Us(5); int eoi; int res = gpib_read_byte(status, &eoi); // handshake complete, clean up lines GPIB_RELEASE(PIN_NRFD); GPIB_RELEASE(PIN_NDAC); // end seq: ATN -> SPD -> UNT GPIB_ASSERT(PIN_ATN); Delay_Us(5); gpib_write_byte(GPIB_CMD_SPD, 0); // disable spoll gpib_write_byte(GPIB_CMD_UNT, 0); // untalk GPIB_RELEASE(PIN_ATN); return res; err: GPIB_RELEASE(PIN_ATN); return -1; } // Data transfer // Send string to device (handles CRLF escape sequences) int gpib_send(uint8_t addr, const char* str) { if (gpib_start_session(addr, SESSION_WRITE) < 0) return -1; int len = strlen(str); for (int i = 0; i < len; i++) { uint8_t b = str[i]; int skip = 0; // escape sequence handling (\n, \r) if (b == '\\' && i < len - 1) { if (str[i + 1] == 'n') { b = 0x0A; skip = 1; } else if (str[i + 1] == 'r') { b = 0x0D; skip = 1; } } // tag the last byte with EOI int is_last = (i == len - 1) || (skip && i == len - 2); if (gpib_write_byte(b, is_last) < 0) { // error during write, try to clean up bus GPIB_ASSERT(PIN_ATN); gpib_write_byte(GPIB_CMD_UNL, 0); GPIB_RELEASE(PIN_ATN); return -1; } if (skip) i++; } // normal cleanup GPIB_ASSERT(PIN_ATN); gpib_write_byte(GPIB_CMD_UNL, 0); GPIB_RELEASE(PIN_ATN); return 0; } // Receive string from device int gpib_receive(uint8_t addr, char* buf, int max_len) { if (gpib_start_session(addr, SESSION_READ) < 0) return -1; int count = 0; int eoi = 0; uint8_t byte; while (count < max_len - 1) { if (gpib_read_byte(&byte, &eoi) < 0) break; buf[count++] = (char)byte; // stop on EOI or LF if (eoi || byte == '\n') break; } buf[count] = 0; // null terminate // ensure listeners are open before asserting ATN GPIB_RELEASE(PIN_NDAC); GPIB_RELEASE(PIN_NRFD); // cleanup: ATN -> UNT GPIB_ASSERT(PIN_ATN); gpib_write_byte(GPIB_CMD_UNT, 0); GPIB_RELEASE(PIN_ATN); return count; } // does not stop on newline and does not NULL terminate int gpib_receive_binary(uint8_t addr, char* buf, int expected_len) { if (gpib_start_session(addr, SESSION_READ) < 0) return -1; int count = 0; int eoi = 0; uint8_t byte; // run until we have the expected count while (count < expected_len) { if (gpib_read_byte(&byte, &eoi) < 0) break; // hw timeout buf[count++] = byte; // only stop on EOI. Ignore '\n' because this is binary data. if (eoi) break; } // ensure listeners are open before asserting ATN GPIB_RELEASE(PIN_NDAC); GPIB_RELEASE(PIN_NRFD); // cleanup: ATN -> UNT GPIB_ASSERT(PIN_ATN); gpib_write_byte(GPIB_CMD_UNT, 0); GPIB_RELEASE(PIN_ATN); return count; } // write then read (for "?" commands) int gpib_query(uint8_t addr, const char* cmd, char* buf, int max_len) { if (gpib_send(addr, cmd) != 0) return -1; Delay_Ms(2); // give device time to process return gpib_receive(addr, buf, max_len); } void gpib_init(void) { // configure control lines as open-drain outputs funPinMode(PIN_EOI, GPIO_Speed_50MHz | GPIO_CNF_OUT_OD); funPinMode(PIN_REN, GPIO_Speed_50MHz | GPIO_CNF_OUT_OD); funPinMode(PIN_ATN, GPIO_Speed_50MHz | GPIO_CNF_OUT_OD); funPinMode(PIN_IFC, GPIO_Speed_50MHz | GPIO_CNF_OUT_OD); funPinMode(PIN_DAV, GPIO_Speed_50MHz | GPIO_CNF_OUT_OD); funPinMode(PIN_NDAC, GPIO_Speed_50MHz | GPIO_CNF_OUT_OD); funPinMode(PIN_NRFD, GPIO_Speed_50MHz | GPIO_CNF_OUT_OD); // SRQ is input with pull-up funPinMode(PIN_SRQ, GPIO_CNF_IN_PUPD); funDigitalWrite(PIN_SRQ, 1); // release all control lines to idle (HIGH) GPIB_RELEASE(PIN_EOI); GPIB_RELEASE(PIN_REN); GPIB_RELEASE(PIN_ATN); GPIB_RELEASE(PIN_IFC); GPIB_RELEASE(PIN_DAV); GPIB_RELEASE(PIN_NDAC); GPIB_RELEASE(PIN_NRFD); // data lines funPinMode(PIN_DIO1, GPIO_Speed_50MHz | GPIO_CNF_OUT_OD); funPinMode(PIN_DIO2, GPIO_Speed_50MHz | GPIO_CNF_OUT_OD); funPinMode(PIN_DIO3, GPIO_Speed_50MHz | GPIO_CNF_OUT_OD); funPinMode(PIN_DIO4, GPIO_Speed_50MHz | GPIO_CNF_OUT_OD); funPinMode(PIN_DIO5, GPIO_Speed_50MHz | GPIO_CNF_OUT_OD); funPinMode(PIN_DIO6, GPIO_Speed_50MHz | GPIO_CNF_OUT_OD); funPinMode(PIN_DIO7, GPIO_Speed_50MHz | GPIO_CNF_OUT_OD); funPinMode(PIN_DIO8, GPIO_Speed_50MHz | GPIO_CNF_OUT_OD); // float data lines (release to HIGH) gpib_write_data(0x00); #ifdef GPIB_DEBUG printf("[GPIB] Asserting IFC...\n"); #endif gpib_interface_clear(); #ifdef GPIB_DEBUG gpib_dump_state("INIT DONE"); // if no device is connected: NRFD/NDAC/DAV should all be 1 // if device is connected: NRFD/NDAC might be 0 #endif } // ------------------------------------ void buzzer_init(void) { funPinMode(PIN_BUZZ, GPIO_Speed_50MHz | GPIO_CNF_OUT_PP); funDigitalWrite(PIN_BUZZ, 0); RCC->APB1PCENR |= RCC_TIM2EN; TIM2->PSC = (FUNCONF_SYSTEM_CORE_CLOCK / 1000000) - 1; TIM2->ATRLR = 250; TIM2->DMAINTENR |= TIM_UIE; NVIC_EnableIRQ(TIM2_IRQn); TIM2->CTLR1 |= TIM_CEN; } void buzzer_set(uint32_t freq_hz) { if (current_buzz_freq == freq_hz) return; current_buzz_freq = freq_hz; if (freq_hz == 0) { buzzer_active = 0; return; } uint16_t reload_val = (uint16_t)(1000000UL / (2 * freq_hz)); TIM2->ATRLR = reload_val; TIM2->CNT = 0; // reset phase only on CHANGE buzzer_active = 1; } void TIM2_IRQHandler(void) __attribute__((interrupt)); void TIM2_IRQHandler(void) { if (TIM2->INTFR & TIM_UIF) { // clr the flag TIM2->INTFR = (uint16_t)~TIM_UIF; if (buzzer_active) { // Toggle PC13 if (GPIOC->OUTDR & (1 << 13)) { GPIOC->BSHR = (1 << (16 + 13)); // Reset (Low) } else { GPIOC->BSHR = (1 << 13); // Set (High) } } else { // ensure low when inactive if (GPIOC->OUTDR & (1 << 13)) { GPIOC->BSHR = (1 << (16 + 13)); } } } } void tone(unsigned int freq_hz, unsigned int duration_ms) { if (freq_hz == 0) { Delay_Ms(duration_ms); return; } buzzer_set(freq_hz); Delay_Ms(duration_ms); buzzer_set(0); } void tone_nb(uint16_t freq, uint32_t duration_ms) { buzzer_set(freq); app.beep_start_ts = millis(); app.beep_duration = duration_ms; app.beep_active = 1; } // "Boot Up" void play_startup_tune() { tone(1500, 100); Delay_Ms(25); tone(2500, 100); Delay_Ms(25); tone(4000, 100); } // ------------------------------------ int HandleSetupCustom(struct _USBState* ctx, int setup_code) { if (ctx->USBFS_SetupReqType & USB_REQ_TYP_CLASS) { switch (setup_code) { case 0x21: // CDC_GET_LINE_CODING ctx->pCtrlPayloadPtr = cdc_line_coding; return 7; case 0x20: // CDC_SET_LINE_CODING case 0x22: // CDC_SET_CONTROL_LINE_STATE return 0; } } return -1; } int HandleInRequest(struct _USBState* ctx __attribute__((unused)), int endp __attribute__((unused)), uint8_t* data __attribute__((unused)), int len __attribute__((unused))) { return 0; } void HandleDataOut(struct _USBState* ctx, int endp, uint8_t* data, int len) { if (endp == 0) { ctx->USBFS_SetupReqLen = 0; } else if (endp == 2) { // Copy to Ring Buffer for (int i = 0; i < len; i++) { uint16_t next_head = (usb_rx_head + 1) % USB_RX_BUF_SIZE; if (next_head != usb_rx_tail) { usb_rx_buffer[usb_rx_head] = data[i]; usb_rx_head = next_head; } } } } static void usb_send_text(const char* str) { if (!app.usb_online) return; int len = strlen(str); int pos = 0; while (pos < len) { int chunk = len - pos; if (chunk > 64) chunk = 64; uint32_t start_time = millis(); int sent = 0; while ((millis() - start_time) < USB_SEND_TIMEOUT_MS) { int result = USBFS_SendEndpointNEW(3, (uint8_t*)(str + pos), chunk, 1); if (result == 0) { sent = 1; break; } } if (!sent) { return; } pos += chunk; } } // pull a line from ring buffer int get_start_command(char* dest_buf, int max_len) { if (usb_rx_head == usb_rx_tail) return 0; uint16_t temp_tail = usb_rx_tail; int len = 0; int found_newline = 0; // Peek for newline while (temp_tail != usb_rx_head) { char c = usb_rx_buffer[temp_tail]; if (c == '\n' || c == '\r') { found_newline = 1; break; } temp_tail = (temp_tail + 1) % USB_RX_BUF_SIZE; len++; if (len >= max_len - 1) break; } if (found_newline) { // copy out for (int i = 0; i < len; i++) { dest_buf[i] = usb_rx_buffer[usb_rx_tail]; usb_rx_tail = (usb_rx_tail + 1) % USB_RX_BUF_SIZE; } dest_buf[len] = 0; // eat newline chars while (usb_rx_tail != usb_rx_head) { char c = usb_rx_buffer[usb_rx_tail]; if (c == '\r' || c == '\n') { usb_rx_tail = (usb_rx_tail + 1) % USB_RX_BUF_SIZE; } else { break; } } return len; } return 0; } // ---------------------------------------- static void handle_usb_state(void) { int raw_status = USB_HW_IS_ACTIVE(); uint32_t now = millis(); // edge detection if (raw_status != app.usb_raw_prev) { app.usb_ts = now; app.usb_raw_prev = raw_status; } // debounce with different thresholds for connect/disconnect uint32_t threshold = raw_status ? USB_DEBOUNCE_CONNECT_MS : USB_DEBOUNCE_DISCONNECT_MS; if ((now - app.usb_ts) > threshold) { // state has been stable long enough if (app.usb_online != raw_status) { app.usb_online = raw_status; if (app.usb_online) usb_rx_tail = usb_rx_head = 0; } } } static void handle_env_sensor(void) { if (!app.env_sensor_present) { return; } uint32_t now = millis(); if ((now - app.env_last_read) >= ENV_SENSOR_READ_INTERVAL_MS) { if (aht20_read(&app.current_env) == AHT20_OK) { app.env_last_read = now; } } } // helper to write text to HP3478A display void dmm_display(const char* text, const char* mode) { // cmp vs shadow buf if (strncmp(app.last_disp_sent, text, HP_DISP_BUF_SIZE) == 0) { return; } // printf("Updating Display: %s\n", text); // update shadow buf strncpy(app.last_disp_sent, text, HP_DISP_BUF_SIZE - 1); // "D[23]" + Text + "\n" snprintf(scratch.disp.full_cmd, sizeof(scratch.disp.full_cmd), "%s%s\n", mode, app.last_disp_sent); // send it gpib_send(app.dmm_addr, scratch.disp.full_cmd); } static inline void dmm_display_normal(void) { gpib_send(app.dmm_addr, HP3478A_DISP_NORMAL); // invalidate cache (we're giving control back to DMM) app.last_disp_sent[0] = '\0'; } void save_dmm_state(void) { gpib_interface_clear(); gpib_send(app.dmm_addr, HP3478A_CMD_STATUS_BYTE); int len = gpib_receive_binary(app.dmm_addr, (char*)app.saved_state_bytes, 5); app.has_saved_state = (len == 5) ? 1 : 0; } void restore_dmm_state(void) { if (!app.has_saved_state) { // default fallback if no state saved gpib_send(app.dmm_addr, HP3478A_DISP_NORMAL HP3478A_FUNC_DC_VOLTS HP3478A_RANGE_AUTO HP3478A_DIGITS_5_5 HP3478A_AUTOZERO_ON HP3478A_TRIG_INTERNAL HP3478A_CMD_MASK_BTN_ONLY); return; } dmm_decoded_state_t state; decode_dmm_state_bytes(app.saved_state_bytes, &state); // "D1 Fx Rx Nx Zx" + "T1 M20" build_restoration_string(scratch.cmd.line_buf, &state); strcat(scratch.cmd.line_buf, HP3478A_TRIG_INTERNAL HP3478A_CMD_MASK_BTN_ONLY); gpib_send(app.dmm_addr, scratch.cmd.line_buf); } void exit_to_passthrough(void) { buzzer_set(0); restore_dmm_state(); gpib_go_to_local(app.dmm_addr); app.current_mode = MODE_PASSTHROUGH; app.data.menu.layer = SUBMENU_NONE; app.menu_pos = 0; app.beep_active = 0; uint32_t now = millis(); app.last_poll_time = now; app.ignore_input_start_ts = now; } void enter_feature_mode(menu_item_t item) { // force display refresh app.last_disp_sent[0] = '\0'; // clean buffer for cmds scratch.cmd.line_buf[0] = '\0'; gpib_remote_enable(1); // make sure REN is asserted // we will hold the decoded state here for REL/STATS dmm_decoded_state_t saved_cfg; switch (item) { case MENU_REL: if (app.has_saved_state) { decode_dmm_state_bytes(app.saved_state_bytes, &saved_cfg); build_restoration_string(scratch.cmd.line_buf, &saved_cfg); strcat(scratch.cmd.line_buf, HP3478A_TRIG_INTERNAL HP3478A_CMD_MASK_BTN_DATA HP3478A_CMD_SRQ_CLEAR); strcpy(app.data.rel.unit, saved_cfg.unit_str); } else { // we have no saved state? don't know relative to WHAT dmm_display("ERR NO STATE", HP3478A_DISP_TEXT_FAST); } gpib_send(app.dmm_addr, scratch.cmd.line_buf); app.current_mode = MODE_FEAT_REL; app.data.rel.offset = 0.0; dmm_display("REL MODE", HP3478A_DISP_TEXT_FAST); break; case MENU_DBM: // F1=DCV, A1=AutoRange (Critical for dBm), N5=5.5d gpib_send(app.dmm_addr, HP3478A_MEAS_AC_VOLTS HP3478A_TRIG_INTERNAL HP3478A_CMD_MASK_BTN_DATA HP3478A_CMD_SRQ_CLEAR); app.current_mode = MODE_FEAT_DBM; dmm_display("DBM 50 OHM", HP3478A_DISP_TEXT_FAST); break; case MENU_TEMP: app.current_mode = MODE_FEAT_TEMP; if (app.temp_sensor == SENS_TYPE_K) { // Thermocouple Setup: // F1: DC Volts // R-2: 30mV Range // Z1: AutoZero On gpib_send(app.dmm_addr, HP3478A_FUNC_DC_VOLTS HP3478A_RANGE_NEG_2 HP3478A_DIGITS_5_5 HP3478A_AUTOZERO_ON HP3478A_TRIG_INTERNAL HP3478A_CMD_MASK_BTN_DATA HP3478A_CMD_SRQ_CLEAR); dmm_display("TEMP TYPE-K", HP3478A_DISP_TEXT_FAST); } else if (app.temp_sensor == SENS_THERMISTOR) { // Thermistor: 2-Wire Ohms (Usually standard for NTC) // Range Auto (NTC varies wildy) gpib_send(app.dmm_addr, HP3478A_FUNC_OHMS_2WIRE HP3478A_RANGE_AUTO HP3478A_DIGITS_5_5 HP3478A_AUTOZERO_ON HP3478A_TRIG_INTERNAL HP3478A_CMD_MASK_BTN_DATA HP3478A_CMD_SRQ_CLEAR); char buf[13]; snprintf(buf, sizeof(buf), "NTC %s", NTC_DEFS[app.temp_ntc_preset].name); dmm_display(buf, HP3478A_DISP_TEXT_FAST); } else { // Resistor Setup (PT1000): // F3=2W / F4=4W // R4=30kOhm Range if (app.temp_wire_mode == WIRE_2W) { gpib_send(app.dmm_addr, HP3478A_FUNC_OHMS_2WIRE HP3478A_RANGE_4 HP3478A_DIGITS_5_5 HP3478A_AUTOZERO_ON HP3478A_TRIG_INTERNAL HP3478A_CMD_MASK_BTN_DATA HP3478A_CMD_SRQ_CLEAR); } else { gpib_send(app.dmm_addr, HP3478A_FUNC_OHMS_4WIRE HP3478A_RANGE_4 HP3478A_DIGITS_5_5 HP3478A_AUTOZERO_ON HP3478A_TRIG_INTERNAL HP3478A_CMD_MASK_BTN_DATA HP3478A_CMD_SRQ_CLEAR); } if (app.temp_sensor == SENS_PT1000) dmm_display("TEMP PT1000", HP3478A_DISP_TEXT_FAST); // else // dmm_display("TEMP THERM", HP3478A_DISP_TEXT_FAST); } break; case MENU_CONT: // F3: 2W Ohm, R0: 30 Ohm Range, N3: 3.5 Digits (fastest ADC), M21 gpib_send(app.dmm_addr, HP3478A_FUNC_OHMS_2WIRE HP3478A_RANGE_1 HP3478A_DIGITS_3_5 HP3478A_AUTOZERO_OFF HP3478A_TRIG_INTERNAL HP3478A_CMD_MASK_BTN_DATA HP3478A_CMD_SRQ_CLEAR); app.current_mode = MODE_FEAT_CONT; dmm_display("CONT MODE", HP3478A_DISP_TEXT_FAST); break; case MENU_DIODE: // F3: 2-Wire Ohms // R3: 3 kOhm Range (1mA Current Through Unknown) // N4: 4.5 Digits // Z0: Auto-Zero OFF gpib_send(app.dmm_addr, HP3478A_FUNC_OHMS_2WIRE HP3478A_RANGE_3 HP3478A_DIGITS_4_5 HP3478A_AUTOZERO_OFF HP3478A_TRIG_INTERNAL HP3478A_CMD_MASK_BTN_DATA HP3478A_CMD_SRQ_CLEAR); app.current_mode = MODE_FEAT_DIODE; app.data.diode.connected = 0; app.data.diode.chirp_start = millis() - DIODE_CHIRP_MS - 1; dmm_display("DIODE TEST", HP3478A_DISP_TEXT_FAST); break; case MENU_XOHM: // H7: High Impedance / Extended Ohm Mode // The DMM puts internal 10M in parallel with input gpib_send(app.dmm_addr, HP3478A_MEAS_OHMS_EXT HP3478A_DIGITS_5_5 HP3478A_TRIG_INTERNAL HP3478A_CMD_MASK_BTN_DATA HP3478A_CMD_SRQ_CLEAR); app.data.xohm.r1 = 0.0; app.data.xohm.calibrated = 0; app.current_mode = MODE_FEAT_XOHM; dmm_display("XOHM 10M REF", HP3478A_DISP_TEXT_FAST); break; case MENU_STATS: if (app.has_saved_state) { decode_dmm_state_bytes(app.saved_state_bytes, &saved_cfg); build_restoration_string(scratch.cmd.line_buf, &saved_cfg); strcat(scratch.cmd.line_buf, HP3478A_TRIG_INTERNAL HP3478A_CMD_MASK_BTN_DATA HP3478A_CMD_SRQ_CLEAR); strcpy(app.data.stats.unit, saved_cfg.unit_str); } else { // fallback strcpy(scratch.cmd.line_buf, HP3478A_FUNC_DC_VOLTS HP3478A_RANGE_AUTO HP3478A_DIGITS_5_5 HP3478A_AUTOZERO_ON HP3478A_TRIG_INTERNAL HP3478A_CMD_MASK_BTN_DATA HP3478A_CMD_SRQ_CLEAR); strcpy(app.data.stats.unit, "VDC"); } gpib_send(app.dmm_addr, scratch.cmd.line_buf); app.current_mode = MODE_FEAT_STATS; // Initialize Stats app.data.stats.min = DBL_MAX; // start impossible high app.data.stats.max = -DBL_MAX; // start impossible low app.data.stats.sum = 0.0; app.data.stats.count = 0; app.data.stats.view_mode = 0; app.data.stats.disp_timer = millis(); dmm_display("STATS INIT", HP3478A_DISP_TEXT_FAST); break; case MENU_EXIT: default: exit_to_passthrough(); break; } } void enter_menu_mode(void) { // force display refresh app.last_disp_sent[0] = '\0'; save_dmm_state(); app.current_mode = MODE_MENU; app.menu_pos = MENU_REL; app.data.menu.timer = millis(); dmm_display("M: REL", HP3478A_DISP_TEXT_FAST); gpib_send(app.dmm_addr, HP3478A_CMD_MASK_BTN_ONLY HP3478A_CMD_SRQ_CLEAR); } void handle_feature_logic(void) { uint8_t stb = 0; gpib_serial_poll(app.dmm_addr, &stb); // exit button (SRQ) if (stb & HP3478A_MASK_KEYBOARD_SRQ) { exit_to_passthrough(); return; } // data ready (Bit 0) if (!(stb & HP3478A_MASK_DATA_READY)) return; // read measurement int len = gpib_receive(app.dmm_addr, scratch.io.raw_data, sizeof(scratch.io.raw_data)); if (len < 0) { // timeout or error // printf("Read Timeout in Feature\n"); app.current_mode = MODE_PASSTHROUGH; app.dmm_online = 0; gpib_interface_clear(); return; } double val = parse_double(scratch.io.raw_data); // overload (HP 3478A sends +9.99990E+9 for OL) int is_overload = 0; if (val < DMM_OL_NEG_THRESHOLD || val > DMM_OL_THRESHOLD) is_overload = 1; // RELATIVE MODE if (app.current_mode == MODE_FEAT_REL) { if (app.data.rel.offset == 0.0) { // waiting to capture the NULL value if (is_overload) { app.data.rel.stable_count = 0; // reset counter if probes are open dmm_display("O.VLD", HP3478A_DISP_TEXT_FAST); } else { // valid reading app.data.rel.stable_count++; if (app.data.rel.stable_count >= REL_STABLE_SAMPLES) { app.data.rel.offset = val; dmm_display("NULL SET", HP3478A_DISP_TEXT_FAST); tone_nb(3000, 50); app.data.rel.stable_count = 0; } else { dmm_display("LOCKING...", HP3478A_DISP_TEXT_FAST); } } } else { // offset is already set if (is_overload) { dmm_display("O.VLD", HP3478A_DISP_TEXT_FAST); } else { double diff = val - app.data.rel.offset; char eff_unit[5]; // prepend 'D' snprintf(eff_unit, sizeof(eff_unit), "D%s", app.data.rel.unit); format_metric_value(scratch.disp.full_cmd, sizeof(scratch.disp.full_cmd), diff, eff_unit, 1); dmm_display(scratch.disp.full_cmd, HP3478A_DISP_TEXT); } } } // dBm MODE else if (app.current_mode == MODE_FEAT_DBM) { if (is_overload) { dmm_display("O.VLD", HP3478A_DISP_TEXT_FAST); } else { // P(mW) = (V^2 / 50) * 1000 = V^2 * 20 double p_mw = (val * val * 20.0); if (p_mw < 1e-9) { // Align -INF to look consistent // Display: "-INF DBM" memset(scratch.disp.full_cmd, ' ', HP_DISP_LEN); scratch.disp.full_cmd[HP_DISP_LEN] = '\0'; memcpy(scratch.disp.full_cmd, "-INF", 4); memcpy(&scratch.disp.full_cmd[8], " DBM", 4); dmm_display(scratch.disp.full_cmd, HP3478A_DISP_TEXT_FAST); } else { double dbm = 10.0 * log10(p_mw); format_metric_value(scratch.disp.full_cmd, sizeof(scratch.disp.full_cmd), dbm, "DBM", 00); dmm_display(scratch.disp.full_cmd, HP3478A_DISP_TEXT); } } } // TEMP MODE else if (app.current_mode == MODE_FEAT_TEMP) { if (is_overload && app.temp_sensor != SENS_TYPE_K) { dmm_display("OPEN / ERR", HP3478A_DISP_TEXT_FAST); } else { double temp_c = 0.0; const char* unit_str = " C"; // TYPE K THERMOCOUPLE if (app.temp_sensor == SENS_TYPE_K) { // 30mV range safety check (Floating input > 50mV) if (fabs(val) > 0.050) { dmm_display("CHECK PROBE", HP3478A_DISP_TEXT_FAST); return; } else { double t_amb; // Cold Junction Compensation (CJC) if (app.env_sensor_present) { t_amb = app.current_env.temp_c_x100 / 100.0; t_amb -= CJC_SELF_HEATING_OFFSET; unit_str = "C (K)"; } else { t_amb = CJC_FALLBACK_TEMP; unit_str = "C (K*)"; // '*' means fallback CJC used } // Type K response is actually NOT linear, this should be a LUT or a // polynomial calculation // Temp = Ambient + (V_meas * Sensitivity) temp_c = t_amb + (val * TYPE_K_SCALE); } } // PT1000 RTD (Callendar-Van Dusen) else if (app.temp_sensor == SENS_PT1000) { if (val < 10.0) { dmm_display("SHORT", HP3478A_DISP_TEXT_FAST); return; } else { double c = RTD_R0 - val; double b = RTD_R0 * RTD_A; double a = RTD_R0 * RTD_B; double disc = (b * b) - (4 * a * c); if (disc >= 0) temp_c = (-b + sqrt(disc)) / (2 * a); else { dmm_display("RANGE ERR", HP3478A_DISP_TEXT_FAST); return; } } } // THERMISTOR (simplified Steinhart-Hart) else { if (val < 10.0) { dmm_display("SHORT", HP3478A_DISP_TEXT_FAST); return; } if (val > 4000000.0) { dmm_display("OPEN", HP3478A_DISP_TEXT_FAST); return; } double r_meas = val; // constants from our preset double r0 = NTC_DEFS[app.temp_ntc_preset].r0; double beta = NTC_DEFS[app.temp_ntc_preset].beta; const double t0_k = 298.15; // 25.0C in Kelvin // 1/T = 1/T0 + (1/B * ln(R/R0)) double ln_ratio = log(r_meas / r0); double inv_t = (1.0 / t0_k) + ((1.0 / beta) * ln_ratio); // convert Kelvin to Celsius temp_c = (1.0 / inv_t) - 273.15; unit_str = "C NTC"; } // Display: "24.5 C" (or "24.5 C (K)") format_metric_value(scratch.disp.full_cmd, sizeof(scratch.disp.full_cmd), temp_c, unit_str, 0); dmm_display(scratch.disp.full_cmd, HP3478A_DISP_TEXT); } } // CONT MODE else if (app.current_mode == MODE_FEAT_CONT) { int is_short = (!is_overload && val < CONT_THRESHOLD_OHMS); // instant beep buzzer_set(is_short ? 2500 : 0); uint32_t now = millis(); if (now - app.data.cont.last_disp_update > CONT_DISP_UPDATE_MS) { app.data.cont.last_disp_update = now; if (is_overload) { dmm_display("OPEN", HP3478A_DISP_TEXT_FAST); } else { format_metric_value(scratch.disp.full_cmd, sizeof(scratch.disp.full_cmd), val, "OHM", 1); dmm_display(scratch.disp.full_cmd, HP3478A_DISP_TEXT); } } } else if (app.current_mode == MODE_FEAT_DIODE) { uint32_t now = millis(); double voltage = is_overload ? 9.9 : (val / 1000.0); uint8_t is_valid_signal = (voltage > DIODE_TH_SHORT && voltage < DIODE_TH_OPEN); if (voltage < DIODE_TH_OPEN) { format_metric_value(scratch.disp.full_cmd, sizeof(scratch.disp.full_cmd), voltage, "VDC", 1); dmm_display(scratch.disp.full_cmd, HP3478A_DISP_TEXT); } else { dmm_display("OPEN", HP3478A_DISP_TEXT); } diode_state_t next_state = app.data.diode.connected; switch (app.data.diode.connected) { case DIODE_STATE_OPEN: case DIODE_STATE_SHORT: if (is_valid_signal) { next_state = DIODE_STATE_CHECKING; app.data.diode.chirp_start = now; } else { // strictly either open or short next_state = (voltage >= DIODE_TH_OPEN) ? DIODE_STATE_OPEN : DIODE_STATE_SHORT; } break; case DIODE_STATE_CHECKING: if (!is_valid_signal) { next_state = DIODE_STATE_SHORT; // signal lost/glitch } else if ((now - app.data.diode.chirp_start) >= DIODE_STABLE_MS) { // has been stable long enough tone_nb(2500, DIODE_CHIRP_MS); next_state = DIODE_STATE_DONE; } break; case DIODE_STATE_DONE: // latch until signal is clearly lost if (!is_valid_signal) { next_state = DIODE_STATE_SHORT; } break; default: next_state = DIODE_STATE_OPEN; break; } app.data.diode.connected = next_state; } // XOHM MODE else if (app.current_mode == MODE_FEAT_XOHM) { // cal phase, measure the internal 10M resistor if (app.data.xohm.calibrated == 0) { // need the probes to be open. Internal R is ~10M if (val > 8.0e6 && val < 12.0e6) { app.data.xohm.r1 = val; // Store R1 app.data.xohm.calibrated = 1; tone_nb(3000, 100); } else { dmm_display("OPEN PROBES", HP3478A_DISP_TEXT_FAST); } } // Rx = (R1 * R2) / (R1 - R2) // R1 = xohm_ref (Internal) // R2 = val (Measured Parallel) else { if (is_overload || val >= (app.data.xohm.r1 - 1000.0)) { dmm_display("OPEN", HP3478A_DISP_TEXT_FAST); } else { double r1 = app.data.xohm.r1; double r2 = val; double rx = (r1 * r2) / (r1 - r2); format_metric_value(scratch.disp.full_cmd, sizeof(scratch.disp.full_cmd), rx, "OHM", 1); dmm_display(scratch.disp.full_cmd, HP3478A_DISP_TEXT); } } } else if (app.current_mode == MODE_FEAT_STATS) { if (is_overload) { dmm_display("O.VLD", HP3478A_DISP_TEXT_FAST); } else { // accumulate math if (val < app.data.stats.min) app.data.stats.min = val; if (val > app.data.stats.max) app.data.stats.max = val; app.data.stats.sum += val; app.data.stats.count++; // rotate display uint32_t now = millis(); if (now - app.data.stats.disp_timer > STATS_CYCLE_TIME_MS) { app.data.stats.view_mode++; if (app.data.stats.view_mode > 3) app.data.stats.view_mode = 0; app.data.stats.disp_timer = now; } // render const char* prefix_str = ""; double val_to_show = val; switch (app.data.stats.view_mode) { case 0: // Live val_to_show = val; break; case 1: // Avg prefix_str = "AVG "; val_to_show = app.data.stats.sum / app.data.stats.count; break; case 2: // Min prefix_str = "MIN "; val_to_show = app.data.stats.min; break; case 3: // Max prefix_str = "MAX "; val_to_show = app.data.stats.max; break; default: app.data.stats.view_mode = 0; break; } // render if (app.data.stats.view_mode == 0) { // live mode format_metric_value(scratch.disp.full_cmd, sizeof(scratch.disp.full_cmd), val_to_show, app.data.stats.unit, 1); } else { // stats mode: prefix (4) + number (8) double abs_v = fabs(val_to_show); double scaled = val_to_show; char suffix = 0; if (abs_v >= 1.0e9) { scaled *= 1.0e-9; suffix = 'G'; } else if (abs_v >= 1.0e6) { scaled *= 1.0e-6; suffix = 'M'; } else if (abs_v >= 1.0e3) { scaled *= 1.0e-3; suffix = 'K'; } char num_buf[16]; double_to_str(num_buf, sizeof(num_buf), scaled, 4); // combine: prefix + number + suffix snprintf(scratch.disp.full_cmd, sizeof(scratch.disp.full_cmd), "%s%s%c ", prefix_str, num_buf, suffix ? suffix : ' '); } // send it dmm_display(scratch.disp.full_cmd, HP3478A_DISP_TEXT); } } } // gens the base string (e.g., "M: TEMP", "S: TYPE K") into // scratch.disp.full_cmd void prepare_menu_base_string(void) { const char* prefix = ""; const char* name = "???"; if (app.data.menu.layer == SUBMENU_NONE) { prefix = "M: "; if (app.menu_pos < MENU_MAX_ITEMS) name = MENU_NAMES[app.menu_pos]; } else if (app.data.menu.layer == SUBMENU_TEMP_SENS) { prefix = "S: "; if (app.menu_pos < SENS_MAX_ITEMS) name = SENSOR_NAMES[app.menu_pos]; } else if (app.data.menu.layer == SUBMENU_TEMP_WIRE) { prefix = "T: "; if (app.menu_pos < WIRE_MAX_ITEMS) name = WIRE_NAMES[app.menu_pos]; } else if (app.data.menu.layer == SUBMENU_TEMP_NTC) { prefix = "N: "; if (app.menu_pos < NTC_MAX_ITEMS) name = NTC_DEFS[app.menu_pos].name; } snprintf(scratch.disp.full_cmd, sizeof(scratch.disp.full_cmd), "%s%s", prefix, name); } void handle_menu_navigation(void) { uint32_t now = millis(); uint32_t elapsed = now - app.data.menu.timer; if (elapsed > MENU_DEBOUNCE_MS) { // only poll GPIB if physical line is asserted if (gpib_check_srq()) { uint8_t stb = 0; gpib_serial_poll(app.dmm_addr, &stb); // check if it was the front panel btn if (stb & HP3478A_MASK_KEYBOARD_SRQ) { // reset timer app.data.menu.timer = now; app.menu_pos++; int max_items = 0; if (app.data.menu.layer == SUBMENU_NONE) max_items = MENU_MAX_ITEMS; else if (app.data.menu.layer == SUBMENU_TEMP_SENS) max_items = SENS_MAX_ITEMS; else if (app.data.menu.layer == SUBMENU_TEMP_WIRE) max_items = WIRE_MAX_ITEMS; else if (app.data.menu.layer == SUBMENU_TEMP_NTC) max_items = NTC_MAX_ITEMS; if (app.menu_pos >= max_items) app.menu_pos = 0; // update display prepare_menu_base_string(); dmm_display(scratch.disp.full_cmd, HP3478A_DISP_TEXT_FAST); // re-arm SRQ gpib_send(app.dmm_addr, HP3478A_CMD_MASK_BTN_ONLY HP3478A_CMD_SRQ_CLEAR); return; } } } prepare_menu_base_string(); // only calculate dots if we are past the initial delay if (elapsed > MENU_SUBLAYER_DELAY_MS) { uint32_t dot_time = elapsed - MENU_SUBLAYER_DELAY_MS; int dots = dot_time / MENU_DOT_INTERVAL_MS; if (dots > 3) dots = 3; for (int i = 0; i < dots; i++) strcat(scratch.disp.full_cmd, "."); } dmm_display(scratch.disp.full_cmd, HP3478A_DISP_TEXT_FAST); if (elapsed > MENU_COMMIT_DELAY_MS) { // L0: main menu if (app.data.menu.layer == SUBMENU_NONE) { if (app.menu_pos == MENU_TEMP) { // sensor select app.data.menu.layer = SUBMENU_TEMP_SENS; app.menu_pos = 0; // default to first sensor app.data.menu.timer = now; prepare_menu_base_string(); dmm_display(scratch.disp.full_cmd, HP3478A_DISP_TEXT_FAST); return; } // enter standard modes enter_feature_mode(app.menu_pos); return; } // L1: sensor select else if (app.data.menu.layer == SUBMENU_TEMP_SENS) { app.temp_sensor = (temp_sensor_t)app.menu_pos; if (app.temp_sensor == SENS_TYPE_K) { // Type K is voltage based so skip wire select enter_feature_mode(MENU_TEMP); } else if (app.temp_sensor == SENS_THERMISTOR) { app.data.menu.layer = SUBMENU_TEMP_NTC; app.menu_pos = 0; // default to 10K app.data.menu.timer = now; prepare_menu_base_string(); dmm_display(scratch.disp.full_cmd, HP3478A_DISP_TEXT_FAST); } else { // wire select (for resistive) app.data.menu.layer = SUBMENU_TEMP_WIRE; app.menu_pos = 0; // default to 2W app.data.menu.timer = now; prepare_menu_base_string(); dmm_display(scratch.disp.full_cmd, HP3478A_DISP_TEXT_FAST); } return; } // L2a: wire select else if (app.data.menu.layer == SUBMENU_TEMP_WIRE) { app.temp_wire_mode = (wire_mode_t)app.menu_pos; enter_feature_mode(MENU_TEMP); return; } // L2b: NTC select else if (app.data.menu.layer == SUBMENU_TEMP_NTC) { app.temp_ntc_preset = (ntc_preset_t)app.menu_pos; enter_feature_mode(MENU_TEMP); return; } } } void app_loop(void) { uint32_t now = millis(); if (app.beep_active) { if ((now - app.beep_start_ts) >= app.beep_duration) { buzzer_set(0); app.beep_active = 0; } } // Passthrough if (app.current_mode == MODE_PASSTHROUGH) { int srq_asserted = gpib_check_srq(); int time_to_poll = (now - app.last_poll_time) >= app.poll_interval; // if disconnected, we only try to reconnect on timer ticks if (!app.dmm_online && !time_to_poll) return; // if online, we poll if SRQ is pulled OR timer expires if (app.dmm_online && !srq_asserted && !time_to_poll) return; app.last_poll_time = now; uint8_t stb = 0; // try to talk to DMM int poll_result = gpib_serial_poll(app.dmm_addr, &stb); if (poll_result != 0) { // poll failed (Timeout/NACK) if (app.dmm_online) { // printf("DMM Lost connection.\n"); app.dmm_online = 0; gpib_interface_clear(); } // slow down polling when offline app.poll_interval = DMM_RECOVERY_DELAY_MS; return; } // got a valid response, check if this is a recovery if (!app.dmm_online) { // printf("DMM Recovered.\n"); app.dmm_online = 1; gpib_send(app.dmm_addr, HP3478A_CMD_MASK_BTN_ONLY HP3478A_CMD_SRQ_CLEAR); gpib_go_to_local(app.dmm_addr); tone_nb(4000, 50); app.poll_interval = POLL_INTERVAL_MS; // restore fast polling return; } // valid and online, check buttons if (stb & HP3478A_MASK_KEYBOARD_SRQ && (now - app.ignore_input_start_ts) > MENU_LOCKOUT_MS) { enter_menu_mode(); } return; } // Nav if (app.current_mode == MODE_MENU) { handle_menu_navigation(); return; } // Features // early exit if no SRQ if (!gpib_check_srq()) { return; } uint8_t stb; if (gpib_serial_poll(app.dmm_addr, &stb) != 0) { // DMM crashed during feature mode // printf("Feature crash: DMM Lost\n"); app.current_mode = MODE_PASSTHROUGH; app.dmm_online = 0; gpib_interface_clear(); return; } // check exit button first (priority) if (stb & HP3478A_MASK_KEYBOARD_SRQ) { exit_to_passthrough(); return; } // handle measurement data ready if (stb & HP3478A_MASK_DATA_READY) { handle_feature_logic(); } } static void cmd_help(void) { static const char* help_text = "\r\n=== HP3478A Internal USB-GPIB v" FW_VERSION " ===\r\n" "\r\n" "Prologix-style Commands:\r\n" " ++addr Set Target GPIB Address (0-30)\r\n" " ++auto <0|1> 0=Off, 1=Read-After-Write\r\n" " ++read Read data from current target\r\n" " ++write Write data to target\r\n" " ++trg Trigger (GET) - Target\r\n" " ++clr Device Clear (SDC) - Target\r\n" " ++dcl Device Clear (DCL) - All Devices\r\n" " ++spoll [A] Serial Poll (Target or Addr A)\r\n" " ++loc Local Mode (Drop REN Line)\r\n" " ++gtl Go To Local (GTL) - Target Only\r\n" " ++llo Local Lockout (Disable front panels)\r\n" " ++ren <0|1> Remote Enable Line control\r\n" " ++ifc Interface Clear (Bus Reset)\r\n" " ++ver Firmware Version\r\n" " ++stat Show configuration\r\n" " ++rst System Reboot\r\n" "\r\n" "HP3478A Internal Commands:\r\n" " ++cont, ++temp, ++rel, ++xohm, ++dbm\r\n" " ++diode, ++math (Min/Max/Avg)\r\n" " ++norm Exit Special Mode\r\n" " ++disp Text message on LCD (Max 12)\r\n" " ++env [temp|hum] Internal Sensor (Default: csv)\r\n" "\r\n" "Usage:\r\n" " Commands starting with ++ are executed locally.\r\n" " All other data is sent to the target GPIB device.\r\n" " Input '?' or '? ' for this help.\r\n"; usb_send_text(help_text); } static void cmd_status(void) { snprintf(scratch.cmd.fmt_buf, sizeof(scratch.cmd.fmt_buf), "Stat:\r\n" " Target Addr: %d\r\n" " Internal DMM: %d\r\n" " Timeout: %lu ms\r\n" " Auto Read: %s\r\n" " Current Mode: %d\r\n" " FW: " FW_VERSION "\r\n", app.target_addr, app.dmm_addr, app.gpib_timeout_ms, app.auto_read ? "ON" : "OFF", app.current_mode); usb_send_text(scratch.cmd.fmt_buf); } static void process_command(void) { if (!get_start_command(scratch.cmd.line_buf, sizeof(scratch.cmd.line_buf))) { return; } char* p_cmd = skip_spaces(scratch.cmd.line_buf); int is_cpp_cmd = (strncmp(p_cmd, "++", 2) == 0); int is_query = (strchr(p_cmd, '?') != NULL); if (is_cpp_cmd) { p_cmd += 2; // skip "++" // 'p_args' will point to the first non-space char after the command word char* p_args = p_cmd; while (*p_args && !isspace((unsigned char)*p_args)) p_args++; // find end of word p_args = skip_spaces(p_args); // find start of args cmd_id_t cmd_id = parse_command_id(p_cmd); switch (cmd_id) { // config case CMD_ADDR: if (*p_args) { int addr = atoi(p_args); if (addr >= 0 && addr <= 30) { app.target_addr = addr; usb_send_text("OK\r\n"); } else usb_send_text("ERR: Invalid Addr\r\n"); } else { // if no arg provided, show current snprintf(scratch.cmd.fmt_buf, sizeof(scratch.cmd.fmt_buf), "%d\r\n", app.target_addr); usb_send_text(scratch.cmd.fmt_buf); } break; case CMD_AUTO: if (*p_args) { app.auto_read = atoi(p_args) ? 1 : 0; usb_send_text("OK\r\n"); } else usb_send_text(app.auto_read ? "1\r\n" : "0\r\n"); break; case CMD_VER: usb_send_text("HP3478A Internal USB-GPIB " FW_VERSION "\r\n"); break; case CMD_STAT: cmd_status(); break; case CMD_HELP: cmd_help(); break; case CMD_RST: NVIC_SystemReset(); break; // data case CMD_READ: goto do_read_operation; case CMD_WRITE: if (*p_args) { gpib_send(app.target_addr, p_args); if (app.auto_read) goto do_read_operation; } break; // GPIB Bus control case CMD_TIMEOUT: if (*p_args) { int val = atoi(p_args); // min 1ms, max 60s if (val > 0 && val < 60000) { app.gpib_timeout_ms = val; usb_send_text("OK\r\n"); } else { usb_send_text("ERR: Range 1-60000\r\n"); } } else { snprintf(scratch.cmd.fmt_buf, sizeof(scratch.cmd.fmt_buf), "%lu\r\n", app.gpib_timeout_ms); usb_send_text(scratch.cmd.fmt_buf); } break; case CMD_TRG: gpib_trigger(app.target_addr); usb_send_text("OK\r\n"); break; case CMD_CLR: gpib_device_clear(app.target_addr); usb_send_text("OK\r\n"); break; case CMD_DCL: gpib_universal_clear(); usb_send_text("OK\r\n"); break; case CMD_IFC: gpib_interface_clear(); usb_send_text("OK\r\n"); break; case CMD_LLO: gpib_local_lockout(); usb_send_text("OK\r\n"); break; case CMD_GTL: gpib_go_to_local(app.target_addr); usb_send_text("OK\r\n"); break; case CMD_LOC: gpib_remote_enable(0); usb_send_text("OK\r\n"); break; case CMD_REN: if (*p_args) { gpib_remote_enable(atoi(p_args)); usb_send_text("OK\r\n"); } else usb_send_text("ERR: Usage ++ren 1|0\r\n"); break; case CMD_SPOLL: { uint8_t poll_addr = (*p_args) ? atoi(p_args) : app.target_addr; uint8_t stb; if (gpib_serial_poll(poll_addr, &stb) == 0) { snprintf(scratch.cmd.fmt_buf, sizeof(scratch.cmd.fmt_buf), "%d\r\n", stb); usb_send_text(scratch.cmd.fmt_buf); } else usb_send_text("ERR: Bus\r\n"); break; } // HP3478A Internal Features case CMD_NORM: exit_to_passthrough(); // ensure REN is back up for normal use gpib_remote_enable(1); usb_send_text("OK\r\n"); break; case CMD_DISP: { int i = 0; while (p_args[i] != 0 && i < HP_DISP_LEN) { char c = p_args[i]; if (c >= 'a' && c <= 'z') c -= 32; scratch.disp.full_cmd[i++] = c; } scratch.disp.full_cmd[i] = 0; dmm_display(scratch.disp.full_cmd, HP3478A_DISP_TEXT_FAST); usb_send_text("OK\r\n"); break; } case CMD_ENV: { if (!app.env_sensor_present) { usb_send_text("ERR: No Sensor\r\n"); return; } double t = app.current_env.temp_c_x100 / 100.0; double h = app.current_env.hum_p_x100 / 100.0; char* arg = skip_spaces(p_args); char out_buf[32]; // temp only if (starts_with_nocase(arg, "temp")) { double_to_str(out_buf, sizeof(out_buf), t, 2); usb_send_text(out_buf); usb_send_text("\r\n"); } // hum only else if (starts_with_nocase(arg, "hum")) { double_to_str(out_buf, sizeof(out_buf), h, 2); usb_send_text(out_buf); usb_send_text("\r\n"); } // CSV format (temp,hum) else { double_to_str(out_buf, 16, t, 2); strcat(out_buf, ","); // fmt humidity into a temp buffer and append char h_buf[16]; double_to_str(h_buf, sizeof(h_buf), h, 2); strcat(out_buf, h_buf); strcat(out_buf, "\r\n"); usb_send_text(out_buf); } break; } // feat entry case CMD_CONT: case CMD_TEMP: case CMD_REL: case CMD_XOHM: case CMD_DBM: case CMD_DIODE: case CMD_MATH: { menu_item_t item = MENU_EXIT; if (cmd_id == CMD_CONT) item = MENU_CONT; else if (cmd_id == CMD_TEMP) item = MENU_TEMP; else if (cmd_id == CMD_REL) item = MENU_REL; else if (cmd_id == CMD_XOHM) item = MENU_XOHM; else if (cmd_id == CMD_DBM) item = MENU_DBM; else if (cmd_id == CMD_DIODE) item = MENU_DIODE; else if (cmd_id == CMD_MATH) item = MENU_STATS; save_dmm_state(); // save before changing enter_feature_mode(item); usb_send_text("OK\r\n"); break; } default: usb_send_text("ERR: Unknown cmd\r\n"); break; } return; } // passthrough mode (not "++") if (gpib_send(app.target_addr, p_cmd) < 0) { usb_send_text("ERR: Send Fail\r\n"); return; } if (is_query || app.auto_read) goto do_read_operation; return; do_read_operation: { int len = gpib_receive(app.target_addr, scratch.io.raw_data, sizeof(scratch.io.raw_data)); if (len > 0) { usb_send_text(scratch.io.raw_data); } else if (is_cpp_cmd || is_query) { usb_send_text("ERR: Read Timeout\r\n"); } } } int main() { SystemInit(); systick_init(); funGpioInitAll(); // Buzzer setup buzzer_init(); // I2C sensor i2c_init(); app.env_sensor_present = aht20_init() == AHT20_OK ? 1 : 0; // GPIB controller gpib_init(); gpib_remote_enable(1); // USB interface USBFSSetup(); // usb_debug = 1; play_startup_tune(); // app state app.current_mode = MODE_PASSTHROUGH; app.usb_online = 0; app.usb_raw_prev = USB_HW_IS_ACTIVE(); app.usb_ts = millis(); app.last_poll_time = 0; app.ignore_input_start_ts = millis() - 2000; app.dmm_online = 0; while (1) { handle_usb_state(); app_loop(); handle_env_sensor(); if (app.usb_online) { process_command(); } } }