#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 ENV_SENSOR_READ_INTERVAL_MS 1000 #define GPIB_TIMEOUT_MS 100 // 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 // 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 0.050f // Volts (below this = SHORT) #define DIODE_TH_OPEN 2.500f // 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-3f #define RTD_B -5.775e-7f #define RTD_R0 1000.0f // Thermistor // TODO: different ranges? 5k, 10k etc.? // This is a 5k NTC!!! kinda useless here #define THERM_A 0.001286f #define THERM_B 0.00023595f #define THERM_C 0.0000000941f // Thermocouple #define CJC_FALLBACK_TEMP 22.0f // 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 4.0f #define TYPE_K_SCALE 24390.24f // 1 / 41uV // dBm #define DBM_REF_Z 50.0f // Stats #define STATS_CYCLE_TIME_MS 3000 // time per screen (Live -> Avg -> Min...) #define STATS_INIT_MIN_VAL 1.0e9f #define STATS_INIT_MAX_VAL -1.0e9f // HP3478A #define HP_DISP_LEN 13 // 13 chars #define CONT_THRESHOLD_OHMS 10.0f // continuity beep threshold #define HP_OVERLOAD_VAL 9.0e9f // HP sends +9.9999E+9 on overload #define REL_STABLE_SAMPLES 3 // filter depth for Relative NULL 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 struct { const char* name; float a; float b; float c; } thermistor_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"}; // Sub-menu states typedef enum { SUBMENU_NONE = 0, SUBMENU_TEMP_SENS, // step 1: sensor Type SUBMENU_TEMP_WIRE // step 2: wire mode (skipped for Type K) } 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 { CONT_SHORT = 0, CONT_OPEN } cont_state_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_PLAYING, // is a diode, chirping DIODE_STATE_DONE // chirped, latched silent } diode_state_t; typedef union { struct { float offset; uint8_t stable_count; } rel; struct { float min; float max; float sum; uint32_t count; uint32_t disp_timer; uint8_t view_mode; } stats; struct { float r1; uint8_t calibrated; } xohm; struct { uint32_t disp_timer; int last_state; } cont; struct { uint8_t connected; // touchy? uint32_t chirp_start; // when we began the touchy } diode; // 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 reserved : 2; // Addresses uint8_t target_addr; uint8_t dmm_addr; // Timers uint32_t usb_ts; uint32_t env_last_read; uint32_t last_poll_time; uint32_t poll_interval; // 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; // Environmental Data aht20_data current_env; // DMM Restore uint8_t saved_state_bytes[5]; // Display shadow buffer char last_disp_sent[HP_DISP_LEN + 1]; // 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}; // Buffers static char cmd_buffer[128]; static char resp_buffer[256]; static char tmp_buffer[128]; static char disp_buffer[HP_DISP_LEN + 1]; // Size: "D3"(2) + Text(12) + "\n"(1) + Null(1) = 16 bytes static char disp_cmd_buffer[2 + HP_DISP_LEN + 1 + 1]; // 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; } void fmt_float(char* buf, size_t size, float val, int precision) { if (val != val) { snprintf(buf, size, "NAN"); return; } if (val > 3.4e38f) { snprintf(buf, size, "INF"); return; } if (val < 0.0f) { *buf++ = '-'; val = -val; size--; } float rounder = 0.5f; for (int i = 0; i < precision; i++) rounder *= 0.1f; val += rounder; uint32_t int_part = (uint32_t)val; float remainder = val - (float)int_part; int len = snprintf(buf, size, "%lu", int_part); if (len < 0 || (size_t)len >= size) return; buf += len; size -= len; if (precision > 0 && size > 1) { *buf++ = '.'; size--; while (precision-- > 0 && size > 1) { remainder *= 10.0f; int digit = (int)remainder; if (digit > 9) digit = 9; *buf++ = '0' + digit; remainder -= digit; size--; } *buf = 0; } } // [NUMBER] + [SPACES] + [UNIT] // assumes buffer is at least HP_DISP_LEN + 1b void format_aligned_display(char* buffer, float value, int precision, const char* suffix) { char num_str[16]; // fmt number to string fmt_float(num_str, sizeof(num_str), value, precision); int num_len = strlen(num_str); int suf_len = strlen(suffix); // reset buffer to spaces memset(buffer, ' ', HP_DISP_LEN); buffer[HP_DISP_LEN] = '\0'; // write number (left aligned) // clamp to max display length int copy_len = (num_len > HP_DISP_LEN) ? HP_DISP_LEN : num_len; memcpy(buffer, num_str, copy_len); // write suffix (right aligned) int suf_start = HP_DISP_LEN - suf_len; if (suf_start < 0) suf_start = 0; memcpy(&buffer[suf_start], suffix, suf_len); } void format_resistance(char* buffer, size_t buf_len, float val) { if (buf_len < HP_DISP_LEN + 1) return; float scaled_val; const char* suffix; int prec; // determine logic if (val >= 1e9f) { scaled_val = val / 1e9f; suffix = " G"; prec = 4; // "1.1234 G" } else if (val >= 1e6f) { scaled_val = val / 1e6f; suffix = " M"; prec = 4; // "10.1234 M" } else if (val >= 1e3f) { scaled_val = val / 1e3f; suffix = " K"; prec = 4; // "100.1234 K" } else { scaled_val = val; suffix = " OHM"; prec = 2; // "100.55 OHM" } format_aligned_display(buffer, scaled_val, prec, suffix); } float parse_float(const char* s) { float res = 0.0f; float fact = 1.0f; int sign = 1; int point_seen = 0; while (*s == ' ') s++; if (*s == '+') s++; else if (*s == '-') { sign = -1; s++; } // parse mantissa while (*s) { if (*s == '.') { point_seen = 1; } else if (*s >= '0' && *s <= '9') { if (point_seen) { fact /= 10.0f; res += (*s - '0') * fact; } else { res = res * 10.0f + (*s - '0'); } } else if (*s == 'E' || *s == 'e') { s++; // skip 'E' int exp = atoi(s); // apply exponent float power = 1.0f; int exp_abs = abs(exp); while (exp_abs--) power *= 10.0f; if (exp > 0) res *= power; else res /= power; break; } else { break; } s++; } return res * sign; } #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) > 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 (auto-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)); } } } } // TODO: maybne don't sleep inside it 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 play_startup_tune() { // "Boot Up" tone(1500, 100); Delay_Ms(20); tone(2500, 100); Delay_Ms(20); tone(4000, 100); } void play_connected_tune() { // "Device Attached" tone(3000, 100); tone(4000, 100); } void play_disconnected_tune() { // "Device Removed" tone(4000, 100); tone(3000, 100); } void beep(int ms) { tone(2500, ms); } // ------------------------------------ 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) { int len = strlen(str); int pos = 0; while (pos < len) { int chunk = len - pos; if (chunk > 64) chunk = 64; USBFS_SendEndpointNEW(3, (uint8_t*)(str + pos), chunk, 1); Delay_Us(250); // yikes 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; play_connected_tune(); } else { play_disconnected_tune(); } } } } 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 // CMD: D2 = Full alphanumeric message void dmm_display(const char* text) { if (strncmp(app.last_disp_sent, text, HP_DISP_LEN) == 0) { return; // text hasn't changed } // upd cache strncpy(app.last_disp_sent, text, HP_DISP_LEN); app.last_disp_sent[HP_DISP_LEN] = 0; // copy command strcpy(disp_cmd_buffer, HP3478A_DISP_TEXT_FAST); // append text strncat(disp_cmd_buffer, text, HP_DISP_LEN); // newline require for D2 and D3 strcat(disp_cmd_buffer, "\n"); gpib_send(app.dmm_addr, disp_cmd_buffer); } 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) { 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; } uint8_t b1 = app.saved_state_bytes[0]; uint8_t b2 = app.saved_state_bytes[1]; // ptrs to string literals const char* cmd_func; const char* cmd_range; const char* cmd_dig; const char* cmd_az; switch ((b1 >> 5) & 0x07) { case 2: cmd_func = HP3478A_FUNC_AC_VOLTS; break; case 3: cmd_func = HP3478A_FUNC_OHMS_2WIRE; break; case 4: cmd_func = HP3478A_FUNC_OHMS_4WIRE; break; case 5: cmd_func = HP3478A_FUNC_DC_CURRENT; break; case 6: cmd_func = HP3478A_FUNC_AC_CURRENT; break; case 7: cmd_func = HP3478A_FUNC_OHMS_EXT; break; default: cmd_func = HP3478A_FUNC_DC_VOLTS; break; } // Decode Range (Bits 4-2) + AutoRange (Byte 2 Bit 1) if (b2 & 0x02) { cmd_range = HP3478A_RANGE_AUTO; } else { // Octal 1=R-2 ... Octal 7=R4 switch ((b1 >> 2) & 0x07) { case 1: cmd_range = HP3478A_RANGE_NEG_2; break; case 2: cmd_range = HP3478A_RANGE_NEG_1; break; case 3: cmd_range = HP3478A_RANGE_0; break; case 4: cmd_range = HP3478A_RANGE_1; break; case 5: cmd_range = HP3478A_RANGE_2; break; case 6: cmd_range = HP3478A_RANGE_3; break; case 7: cmd_range = HP3478A_RANGE_4; break; default: cmd_range = HP3478A_RANGE_0; break; } } // Decode Digits (Bits 1-0) switch (b1 & 0x03) { case 2: cmd_dig = HP3478A_DIGITS_4_5; break; case 3: cmd_dig = HP3478A_DIGITS_3_5; break; default: cmd_dig = HP3478A_DIGITS_5_5; break; } // Decode AutoZero (Byte 2 Bit 2) cmd_az = (b2 & 0x04) ? HP3478A_AUTOZERO_ON : HP3478A_AUTOZERO_OFF; // "D1 Fx Rx Nx Zx T1 M20" strcpy(cmd_buffer, HP3478A_DISP_NORMAL); strcat(cmd_buffer, cmd_func); strcat(cmd_buffer, cmd_range); strcat(cmd_buffer, cmd_dig); strcat(cmd_buffer, cmd_az); strcat(cmd_buffer, HP3478A_TRIG_INTERNAL HP3478A_CMD_MASK_BTN_ONLY); gpib_send(app.dmm_addr, cmd_buffer); } void exit_to_passthrough(void) { buzzer_set(0); // mute 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.last_poll_time = millis(); Delay_Ms(MENU_DEBOUNCE_MS); } void enter_feature_mode(menu_item_t item) { // force display refresh app.last_disp_sent[0] = '\0'; gpib_remote_enable(1); // assert REN Delay_Ms(20); switch (item) { case MENU_REL: gpib_send(app.dmm_addr, HP3478A_FUNC_OHMS_2WIRE HP3478A_DIGITS_5_5 HP3478A_TRIG_INTERNAL HP3478A_CMD_MASK_BTN_DATA HP3478A_CMD_SRQ_CLEAR); app.current_mode = MODE_FEAT_REL; app.data.rel.offset = 0.0f; dmm_display("REL MODE"); 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"); 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"); } else { // Resistor Setup (PT1000/Therm): // 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); } gpib_send(app.dmm_addr, tmp_buffer); if (app.temp_sensor == SENS_PT1000) dmm_display("TEMP PT1000"); else dmm_display("TEMP THERM"); } 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; app.data.cont.last_state = -1; app.data.cont.disp_timer = millis(); dmm_display("CONT MODE"); 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"); 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 = 0.0f; app.data.xohm.calibrated = 0; app.current_mode = MODE_FEAT_XOHM; dmm_display("XOHM 10M REF"); break; case MENU_STATS: // F1: DC Volts // A1: Auto Range // N5: 5.5 Digit // Z1: Auto Zero ON // T1: Internal Trigger gpib_send(app.dmm_addr, 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); app.current_mode = MODE_FEAT_STATS; // Initialize Stats app.data.stats.min = STATS_INIT_MIN_VAL; // start impossible high app.data.stats.max = STATS_INIT_MAX_VAL; // start impossible low app.data.stats.sum = 0.0f; app.data.stats.count = 0; app.data.stats.view_mode = 0; app.data.stats.disp_timer = millis(); dmm_display("STATS INIT"); 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(); uint32_t now = millis(); app.current_mode = MODE_MENU; app.menu_pos = MENU_REL; app.data.menu.timer = now; dmm_display("M: REL"); gpib_send(app.dmm_addr, HP3478A_CMD_MASK_BTN_ONLY HP3478A_CMD_SRQ_CLEAR); Delay_Ms(200); } 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, resp_buffer, sizeof(resp_buffer)); 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; } float val = parse_float(resp_buffer); // overload (HP 3478A sends +9.99990E+9 for OL) int is_overload = (val > HP_OVERLOAD_VAL); // RELATIVE MODE if (app.current_mode == MODE_FEAT_REL) { if (app.data.rel.offset == 0.0f) { // 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"); } 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"); tone(3000, 50); app.data.rel.stable_count = 0; } else { dmm_display("LOCKING..."); } } } else { // offset is already set if (is_overload) { dmm_display("O.VLD"); } else { float diff = val - app.data.rel.offset; fmt_float(disp_buffer, sizeof(disp_buffer), diff, 4); // Display: "1.2345 D" format_aligned_display(disp_buffer, diff, 4, " D"); dmm_display(disp_buffer); } } } // dBm MODE else if (app.current_mode == MODE_FEAT_DBM) { if (is_overload) { dmm_display("O.VLD"); } else { // P(mW) = (V^2 / 50) * 1000 = V^2 * 20 float p_mw = (val * val * 20.0f); if (p_mw < 1e-9f) { // Align -INF to look consistent // Display: "-INF DBM" memset(disp_buffer, ' ', 12); disp_buffer[12] = '\0'; memcpy(disp_buffer, "-INF", 4); memcpy(&disp_buffer[8], " DBM", 4); dmm_display(disp_buffer); } else { float dbm = 10.0f * log10f(p_mw); // Display: "-14.20 DBM" format_aligned_display(disp_buffer, dbm, 2, " DBM"); dmm_display(disp_buffer); } } } // TEMP MODE else if (app.current_mode == MODE_FEAT_TEMP) { if (is_overload && app.temp_sensor != SENS_TYPE_K) { dmm_display("OPEN / ERR"); } else { float temp_c = 0.0f; const char* unit_str = " C"; // 1. TYPE K THERMOCOUPLE if (app.temp_sensor == SENS_TYPE_K) { // 30mV range safety check (Floating input > 50mV) if (fabsf(val) > 0.05f) { dmm_display("CHECK PROBE"); return; } else { float t_amb; // Cold Junction Compensation (CJC) if (app.env_sensor_present) { // Convert int(2450) to 24.50 t_amb = (float)app.current_env.temp_c_x100 / 100.0f; 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); } } // 2. PT1000 RTD (Callendar-Van Dusen) else if (app.temp_sensor == SENS_PT1000) { if (val < 10.0f) { dmm_display("SHORT"); } else { float c = RTD_R0 - val; float b = RTD_R0 * RTD_A; float a = RTD_R0 * RTD_B; float disc = (b * b) - (4 * a * c); if (disc >= 0) temp_c = (-b + sqrtf(disc)) / (2 * a); else { dmm_display("RANGE ERR"); return; } } } // 3. THERMISTOR (Steinhart-Hart) else { if (val < 10.0f) { dmm_display("SHORT"); } else { // protect against log(0) float r = (val < 1.0f) ? 1.0f : val; float lr = logf(r); float lr3 = lr * lr * lr; float inv_t = THERM_A + (THERM_B * lr) + (THERM_C * lr3); temp_c = (1.0f / inv_t) - 273.15f; } } // Display: "24.5 C" (or "24.5 C (K)") format_aligned_display(disp_buffer, temp_c, 1, unit_str); dmm_display(disp_buffer); } } // CONT MODE else if (app.current_mode == MODE_FEAT_CONT) { int is_short = (!is_overload && val < CONT_THRESHOLD_OHMS); // beep if (is_short) { buzzer_set(2000); // 2kHz tone } else { buzzer_set(0); } // display logic uint32_t now = millis(); // force update if state changed or timeout if ((is_short != app.data.cont.last_state) || (now - app.data.cont.disp_timer > 200)) { if (is_overload) { dmm_display("OPEN"); } else { if (val < 1000.0f) { // Normalize low ohms to look like standard ohms mode // "10.5 OHM" format_aligned_display(disp_buffer, val, 1, " OHM"); } else { // shouldn't happen in 300 range :) format_resistance(disp_buffer, sizeof(disp_buffer), val); } dmm_display(disp_buffer); } app.data.cont.last_state = is_short; app.data.cont.disp_timer = now; } } else if (app.current_mode == MODE_FEAT_DIODE) { uint32_t now = millis(); float voltage = is_overload ? 9.9f : (val / 1000.0f); uint8_t is_valid_signal = (voltage > DIODE_TH_SHORT && voltage < DIODE_TH_OPEN); if (voltage < DIODE_TH_OPEN) { format_aligned_display(disp_buffer, voltage, 4, "VDC"); dmm_display(disp_buffer); } else { dmm_display("OPEN"); } diode_state_t next_state = app.data.diode.connected; uint8_t request_buzzer = 0; 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) { next_state = DIODE_STATE_PLAYING; app.data.diode.chirp_start = now; request_buzzer = 1; } break; case DIODE_STATE_PLAYING: request_buzzer = 1; if ((now - app.data.diode.chirp_start) >= 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; buzzer_set(request_buzzer ? 2500 : 0); } // 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 > 8.0e6f && val < 12.0e6f) { app.data.xohm.r1 = val; // Store R1 app.data.xohm.calibrated = 1; tone(3000, 100); dmm_display("READY"); Delay_Ms(500); } else { dmm_display("OPEN PROBES"); } } // Rx = (R1 * R2) / (R1 - R2) // R1 = xohm_ref (Internal) // R2 = val (Measured Parallel) else { if (is_overload || val >= (app.data.xohm.r1 - 1000.0f)) { dmm_display("OPEN"); } else { float r1 = app.data.xohm.r1; float r2 = val; float rx = (r1 * r2) / (r1 - r2); format_resistance(disp_buffer, sizeof(disp_buffer), rx); dmm_display(disp_buffer); } } } else if (app.current_mode == MODE_FEAT_STATS) { if (is_overload) { dmm_display("O.VLD"); } 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 += (double)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 char prefix[5]; // 3-char prefix + space float val_to_show = 0.0f; switch (app.data.stats.view_mode) { case 0: // Live Value strcpy(prefix, ""); val_to_show = val; break; case 1: // Average strcpy(prefix, "AVG "); val_to_show = app.data.stats.sum / app.data.stats.count; break; case 2: // Minimum strcpy(prefix, "MIN "); val_to_show = app.data.stats.min; break; case 3: // Maximum strcpy(prefix, "MAX "); val_to_show = app.data.stats.max; break; default: strcpy(prefix, "ERR "); val_to_show = val; app.data.stats.view_mode = 0; break; } int offset = snprintf(disp_buffer, sizeof(disp_buffer), "%s", prefix); if (offset >= 0 && offset < (int)sizeof(disp_buffer)) { fmt_float(disp_buffer + offset, sizeof(disp_buffer) - offset, val_to_show, 4); } dmm_display(disp_buffer); } } } // gens the base string (e.g., "M: TEMP", "S: TYPE K") into disp_buffer 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]; } snprintf(disp_buffer, sizeof(disp_buffer), "%s%s", prefix, name); } void handle_menu_navigation(void) { uint32_t now = millis(); uint32_t elapsed = now - app.data.menu.timer; // nav: check SRQ (next item) if (gpib_check_srq()) { uint8_t stb = 0; gpib_serial_poll(app.dmm_addr, &stb); // only 4b (front panel button SRQ) if (stb & HP3478A_MASK_KEYBOARD_SRQ) { if (elapsed < MENU_DEBOUNCE_MS) { // we polled, so STB is clear on DMM. Just return. return; } app.data.menu.timer = now; // reset the "hover" timer 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; if (app.menu_pos >= max_items) app.menu_pos = 0; // update display immediately prepare_menu_base_string(); dmm_display(disp_buffer); // re-arm SRQ gpib_send(app.dmm_addr, HP3478A_CMD_MASK_BTN_ONLY HP3478A_CMD_SRQ_CLEAR); Delay_Ms(MENU_DEBOUNCE_MS); 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(disp_buffer, "."); } dmm_display(disp_buffer); 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(disp_buffer); 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 { // 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(disp_buffer); } return; } // L2: 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; } } } void app_loop(void) { uint32_t now = millis(); // 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(4000, 50); app.poll_interval = POLL_INTERVAL_MS; // restore fast polling return; } // valid and online, check buttons if (stb & HP3478A_MASK_KEYBOARD_SRQ) { 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" " ++conf 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(tmp_buffer, sizeof(tmp_buffer), "Stat:\r\n" " Target Addr: %d\r\n" " Internal DMM: %d\r\n" " Auto Read: %s\r\n" " Current Mode: %d\r\n" " FW: " FW_VERSION "\r\n", app.target_addr, app.dmm_addr, app.auto_read ? "ON" : "OFF", app.current_mode); usb_send_text(tmp_buffer); } static void process_command(void) { if (!get_start_command(cmd_buffer, sizeof(cmd_buffer))) { return; } int is_query = 0; char* p_cmd = skip_spaces(cmd_buffer); int is_cpp_cmd = (strncmp(p_cmd, "++", 2) == 0); if (app.current_mode != MODE_PASSTHROUGH) { buzzer_set(0); app.current_mode = MODE_PASSTHROUGH; dmm_display_normal(); gpib_remote_enable(1); // ensure REN matches state } if (is_cpp_cmd) { // move past "++" p_cmd += 2; // '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: ADDR if (starts_with_nocase(p_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(tmp_buffer, sizeof(tmp_buffer), "%d\r\n", app.target_addr); usb_send_text(tmp_buffer); } } // CMD: WRITE else if (starts_with_nocase(p_cmd, "write")) { // sends the rest of the string (p_args) to GPIB if (*p_args) { gpib_send(app.target_addr, p_args); if (app.auto_read) goto do_read_operation; // jmp to read block } } // CMD: READ else if (starts_with_nocase(p_cmd, "read")) { goto do_read_operation; } // CMD: AUTO else if (starts_with_nocase(p_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"); } } // CMD: TRG else if (starts_with_nocase(p_cmd, "trg")) { gpib_trigger(app.target_addr); usb_send_text("OK\r\n"); } // CMD: STATUS / STAT else if (starts_with_nocase(p_cmd, "stat")) { cmd_status(); } // CMD: CLR else if (starts_with_nocase(p_cmd, "clr")) { gpib_device_clear(app.target_addr); usb_send_text("OK\r\n"); } // CMD: REN (Remote Enable) else if (starts_with_nocase(p_cmd, "ren")) { if (*p_args) { int state = atoi(p_args); gpib_remote_enable(state); usb_send_text("OK\r\n"); } else { usb_send_text("usage: ++ren 1|0\r\n"); } } // CMD: IFC (Interface Clear) else if (starts_with_nocase(p_cmd, "ifc")) { gpib_interface_clear(); usb_send_text("OK\r\n"); } // CMD: SPOLL (Serial Poll) else if (starts_with_nocase(p_cmd, "spoll")) { uint8_t poll_addr = app.target_addr; if (*p_args) { int arg = atoi(p_args); if (arg >= 0 && arg <= 30) poll_addr = arg; } uint8_t stb; if (gpib_serial_poll(poll_addr, &stb) == 0) { // print status byte as dec snprintf(tmp_buffer, sizeof(tmp_buffer), "%d\r\n", stb); usb_send_text(tmp_buffer); } else { usb_send_text("ERR: Bus\r\n"); } } // CMD: LLO (Local Lockout) else if (starts_with_nocase(p_cmd, "llo")) { gpib_local_lockout(); usb_send_text("OK\r\n"); } // CMD: DCL (Universal Clear) else if (starts_with_nocase(p_cmd, "dcl")) { gpib_universal_clear(); usb_send_text("OK\r\n"); } // CMD: GTL (Go To Local) else if (starts_with_nocase(p_cmd, "gtl")) { gpib_go_to_local(app.target_addr); usb_send_text("OK\r\n"); } // HP3478A Internal else if (starts_with_nocase(p_cmd, "cont")) enter_feature_mode(MENU_CONT); else if (starts_with_nocase(p_cmd, "temp")) enter_feature_mode(MENU_TEMP); else if (starts_with_nocase(p_cmd, "rel")) enter_feature_mode(MENU_REL); else if (starts_with_nocase(p_cmd, "xohm")) enter_feature_mode(MENU_XOHM); else if (starts_with_nocase(p_cmd, "dbm")) enter_feature_mode(MENU_DBM); else if (starts_with_nocase(p_cmd, "diode")) enter_feature_mode(MENU_DIODE); else if (starts_with_nocase(p_cmd, "math")) enter_feature_mode(MENU_STATS); else if (starts_with_nocase(p_cmd, "norm")) exit_to_passthrough(); else if (starts_with_nocase(p_cmd, "disp")) { int i = 0; while (p_args[i] != 0 && i < 12) { char c = p_args[i]; if (c >= 'a' && c <= 'z') { c -= 32; } disp_buffer[i] = c; i++; } disp_buffer[i] = 0; dmm_display(disp_buffer); usb_send_text("OK\r\n"); } // SYSTEM else if (starts_with_nocase(p_cmd, "loc")) { gpib_remote_enable(0); usb_send_text("OK\r\n"); } else if (starts_with_nocase(p_cmd, "rst")) { usb_send_text("Rebooting...\r\n"); Delay_Ms(100); NVIC_SystemReset(); } else if (starts_with_nocase(p_cmd, "ver")) { usb_send_text("HP3478A Internal GPIB " FW_VERSION "\r\n"); } else if (starts_with_nocase(p_cmd, "help") || starts_with_nocase(p_cmd, "?")) { cmd_help(); } else if (starts_with_nocase(p_cmd, "env")) { if (!app.env_sensor_present) { usb_send_text("ERR: No Sensor\r\n"); return; } float t = (float)app.current_env.temp_c_x100 / 100.0f; float h = (float)app.current_env.hum_p_x100 / 100.0f; char* arg = skip_spaces(p_args); char out_buf[32]; // temp only if (starts_with_nocase(arg, "temp")) { fmt_float(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")) { fmt_float(out_buf, sizeof(out_buf), h, 2); usb_send_text(out_buf); usb_send_text("\r\n"); } // CSV format (temp,hum) else { fmt_float(out_buf, 16, t, 2); strcat(out_buf, ","); // fmt humidity into a temp buffer and append char h_buf[16]; fmt_float(h_buf, sizeof(h_buf), h, 2); strcat(out_buf, h_buf); strcat(out_buf, "\r\n"); usb_send_text(out_buf); } } else { usb_send_text("ERR: Unknown Command\r\n"); } return; // end of ++ } // PASSTHROUGH MODE // check for query '?' to trigger implicit read is_query = (strchr(p_cmd, '?') != NULL); if (gpib_send(app.target_addr, p_cmd) < 0) { usb_send_text("ERR: Send Fail\r\n"); return; } // check if we should read back if (is_query || app.auto_read) { goto do_read_operation; } return; do_read_operation: { int len = gpib_receive(app.target_addr, resp_buffer, sizeof(resp_buffer)); if (len > 0) { usb_send_text(resp_buffer); } 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 = millis(); while (1) { uint8_t status_byte; if (gpib_serial_poll(app.dmm_addr, &status_byte) == 0) { // printf("Device Found (Stb: 0x%02X)\n", status_byte); gpib_send(app.dmm_addr, HP3478A_CMD_MASK_BTN_ONLY HP3478A_CMD_SRQ_CLEAR); gpib_go_to_local(app.dmm_addr); break; } Delay_Ms(100); } app.dmm_online = 1; while (1) { handle_usb_state(); app_loop(); handle_env_sensor(); if (app.usb_online) { process_command(); } } }