feat: add ++dmm_loop cmd

++dmm_loop <0|1> to disable the HP3478A DMM loop, if for some reason the
DMM app loop is interfering with the GPIB bus when used as a USB-GPIB
controller

inc/config.h

@@ -30,7 +30,7 @@
 #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 100        // Button press dead-time
-#define MENU_LOCKOUT_MS 1000  // How long to ignore SRQ for after exiting menu
+#define MENU_LOCKOUT_MS 200  // How long to ignore SRQ for after exiting menu
 
 // Polling
 #define POLL_INTERVAL_MS 100        // 10Hz polling when in Passthrough
@@ -76,6 +76,7 @@
 #define BUZZER_CHIRP_HZ 3000
 #define BUZZER_CHIRP_MS 75
 #define BUZZER_CONT_HZ 2500
+#define BUZZER_ONLINE_TUNE 0  // todo: add to conf
 
 // #define LOCAL_COMMIT 1
 

main.c

@@ -65,6 +65,7 @@ typedef enum {
   CMD_ADDR,      // Set GPIB primary address
   CMD_MODE,      // Set Controller vs Device mode (we're always the controller)
   CMD_TIMEOUT,   // Set read timeouts
+  CMD_DMM_LOOP,  // Toggle extra HP3478A features
 
   // Data transport/formatting
   CMD_READ,        // Read data from bus
@@ -273,7 +274,8 @@ typedef struct {
   uint8_t dmm_online : 1;
   uint8_t has_saved_state : 1;
   uint8_t tone_timer_pending : 1;
-  uint8_t reserved : 2;
+  uint8_t dmm_loop : 1;
+  uint8_t reserved : 1;
 
   uint32_t usb_timeout_cycles;  // calculated from sys_cfg.usb_timeout_target_ms
 
@@ -346,6 +348,7 @@ static const cmd_entry_t COMMAND_TABLE[] = {
     {"mode", CMD_MODE},    // 0=Device, 1=Controller
     {"tmo", CMD_TIMEOUT},  // Set read timeout
     {"read_tmo_ms", CMD_TIMEOUT},
+    {"dmm_loop", CMD_DMM_LOOP},  // Toggle extra feats
 
     // Protocol/formatting
     {"auto", CMD_AUTO},  // Auto-read data after write
@@ -608,6 +611,8 @@ inline static void config_apply_to_app(void) {
   app.usb_timeout_cycles =
       ((FUNCONF_SYSTEM_CORE_CLOCK / 1000 * sys_cfg.usb_timeout_target_ms) /
        CYCLES_PER_LOOP);
+  app.dmm_loop = 1;  // again, preferably read from config if someone wants this
+                     // to be persistent
 }
 
 static void config_reset_defaults(void) {
@@ -1929,11 +1934,10 @@ static void handle_env_sensor(void) {
 
   uint32_t now = millis();
 
-  if ((now - app.env_last_read) >= sys_cfg.env_sensor_read_interval_ms) {
+  if (((now - app.env_last_read) >= sys_cfg.env_sensor_read_interval_ms) &&
-    if (aht20_read(&app.current_env) == AHT20_OK) {
+      aht20_read(&app.current_env) == AHT20_OK) {
     app.env_last_read = now;
   }
-  }
 }
 
 // helper to write text to HP3478A display
@@ -2765,6 +2769,7 @@ static void cmd_help(void) {
       "  ++eor <0-7>       Read Stop:  0:CRLF ... 7:EOI-Only\r\n"
       "  ++eot_enable <B>  Append extra char to read output\r\n"
       "  ++eot_char <dec>  The char to append\r\n"
+      "  ++dmm_loop <0|1>  Toggle HP3478A loop, if it conflicts w/ GPIB bus\r\n"
       "\r\n"
       "[System Configuration]\r\n"
       "  ++config          List all configurable parameters\r\n"
@@ -2808,10 +2813,12 @@ static void cmd_status(void) {
            "EOR : %d\r\n"
            "EOI : %d\r\n"
            "EOT : %s (%d)\r\n"
-           "SRQ : %d\r\n",
+           "SRQ : %d\r\n"
+           "DMM_LOOP : %d\r\n",
            sys_cfg.target_addr, sys_cfg.gpib_timeout_ms, sys_cfg.auto_read,
            sys_cfg.eos_mode, sys_cfg.eor_mode, sys_cfg.eoi_assert,
-           sys_cfg.eot_enable ? "ON" : "OFF", sys_cfg.eot_char, srq);
+           sys_cfg.eot_enable ? "ON" : "OFF", sys_cfg.eot_char, srq,
+           app.dmm_loop);
 
   usb_send_text(scratch.cmd.fmt_buf);
 }
@@ -2948,6 +2955,16 @@ static void process_command(void) {
         }
         break;
 
+      case CMD_DMM_LOOP:
+        if (*p_args) {
+          app.dmm_loop = (atoi(p_args) ? true : false);
+          exit_to_passthrough();
+          gpib_interface_clear();
+        } else {
+          usb_send_text(app.dmm_loop ? "1\r\n" : "0\r\n");
+        }
+        break;
+
       case CMD_SAVECFG:
         config_save();
         break;
@@ -3277,7 +3294,7 @@ do_read_operation: {
 }
 }
 
-static void app_loop(void) {
+static void dmm_loop(void) {
   uint32_t now = millis();
 
   if (app.tone_timer_pending) {
@@ -3322,8 +3339,9 @@ static void app_loop(void) {
       gpib_interface_clear();
 
       app.dmm_online = true;
+#if defined(BUZZER_ONLINE_TUNE) && BUZZER_ONLINE_TUNE
       play_tune(ONLINE_NOTES);
-
+#endif
       gpib_send(sys_cfg.dmm_addr,
                 HP3478A_CMD_MASK_BTN_ONLY HP3478A_CMD_SRQ_CLEAR);
       gpib_go_to_local(sys_cfg.dmm_addr);
@@ -3408,7 +3426,9 @@ int main() {
   while (1) {
     handle_usb_state();
     usb_process_tx();
-    app_loop();
+    if (app.dmm_loop) {
+      dmm_loop();
+    }
     handle_env_sensor();
 
     if (app.usb_online) {