Added software reset

fw/Core/Inc/main.h

@@ -96,6 +96,7 @@ int8_t uart_enable_interrupts(void);
 #endif
 /* USER CODE BEGIN Private defines */
 #define MEASUREMENT_PERIOD_MS		600000
+#define RESET_MAGIC_NUMBER 			0xABCD
 
 extern uint16_t usart2_rx_message_index;
 extern uint16_t usart2_rx_message_len;

fw/Core/Src/main.c

@@ -89,7 +89,8 @@ enum
 	REGISTER_NUM_CO2_ALERT_LIMIT2 = 40005,
 	REGISTER_NUM_SCD4x_T_OFFSET = 40006,
 	REGISTER_NUM_MODBUS_ADDR = 40007,
-	REGISTER_NUM_BAUDRATE = 40008
+	REGISTER_NUM_BAUDRATE = 40008,
+	REGISTER_NUM_RESET_DEVICE = 40100
 } config_registers_numbers;
 
 enum
@@ -931,6 +932,14 @@ int8_t modbus_slave_callback(modbus_transaction_t *transaction)
 						sensor_config.baudrate_index = (uint16_t) (transaction->holding_registers[i]);
 						baudrate_changed = 1;
 						break;
+					case REGISTER_NUM_RESET_DEVICE:
+						if (transaction->holding_registers[i] == 0xABCD) {
+							/* software reset */
+							NVIC_SystemReset();
+						} else {
+							return MODBUS_ERROR_OUT_OF_BOUNDS;
+						}
+						break;
 					default:
 						return MODBUS_ERROR_FUNCTION_NOT_IMPLEMENTED;
 				}

tests/query_device.py

@@ -8,7 +8,7 @@ f'''{argv[0]} ADDR [BAUDRATE] [{{read [REGISTER ...] | write VALUE REGISTER}}]
 where:
     - ADDR is Modbus address (use 0 for broadcast; note that only write can be broadcast)
     - BAUDRATE is (optional) baud rate; default value is 19200
-    - action can be "read", "write" or can be omitted (defaults to "read all")
+    - action can be "read", "write", "reset" or it can be omitted completely (defaults to "read all")
     - REGISTER can be either human-friendly register name (e.g. "CO2") or register number (30001)
     - read may have list of REGISTER arguments (combining both register numbers and names)
     - VALUE is 16-bit integer in decimal format
@@ -78,7 +78,7 @@ while arg_index < len(argv):
 # sanity check
 if not action:
     action = 'all'
-if action != 'read' and action != 'write' and action != 'all':
+if action != 'read' and action != 'write' and action != 'all' and action != 'reset':
     print(f'Unknown action {action}')
     exit(-4)
 if action == 'write' and value == None:
@@ -140,4 +140,11 @@ elif action == 'write':
     except ValueError:
         print(f'Register number {reg_number} cannot be written')
         exit(-9)
+elif action == 'reset':
+    if not s.reset():
+        # reset should throw NoResponse; if it doesn't, reset failed
+        print('Device reset failed!')
+    else:
+        print('---- Device reset ----')
+
 exit(0)

tests/sensor.py

@@ -27,6 +27,8 @@ class Sensor():
             'SCD4x_temperature_offset': 40006, \
             'MODBUS_address': 40007, \
             'baudrate': 40008 }
+    reset_register = 40100
+    reset_magic_number = 0xABCD
     # readout and error counters
     readout_total = 0
     readout_error_invalid_response = 0 # checksum error: bus transmission corrupted?
@@ -49,6 +51,12 @@ class Sensor():
     def close(self):
         self.serial.serial.close()
         self.serial = None
+    def reset(self):
+        try:
+            self.write_register(self.reset_register, self.reset_magic_number)
+            return False # got answer => failed to reset
+        except minimalmodbus.NoResponseError:
+            return True # no answer => reset successful
     # High level read functions
     @property
     def CO2(self):