Moved MODBUS callback back to main

fw/Core/Src/i2c.c

@@ -6,6 +6,7 @@
  */
 
 #include "i2c.h"
+#include "stm32l0xx_ll_lpuart.h"
 
 i2c_context_t *i2c_context;
 
@@ -20,6 +21,10 @@ int i2c_init(i2c_context_t *context)
 
 int i2c_transmit(uint8_t address, uint8_t *buffer, int len)
 {
+	/* prevent interrupts during I2C communication (e.g. collision with MODBUS) */
+//	LL_LPUART_Disable(LPUART1);
+//	LL_LPUART_DisableIT_RXNE(LPUART1);
+//	__disable_irq();
 	LL_I2C_HandleTransfer(i2c_context->i2c, address, LL_I2C_ADDRSLAVE_7BIT, len,
 			LL_I2C_MODE_AUTOEND, LL_I2C_GENERATE_START_WRITE);
 	int i = 0;
@@ -41,11 +46,17 @@ int i2c_transmit(uint8_t address, uint8_t *buffer, int len)
 		// is raised everytime len != number of TXed bytes
 		return I2C_ERROR_TX_INCOMPLETE;
 	}
+//	__enable_irq();
+//	LL_LPUART_Enable(LPUART1);
+//	LL_LPUART_EnableIT_RXNE(LPUART1);
 	return I2C_OK;
 }
 
 int i2c_receive(uint8_t address, uint8_t *buffer, int len)
 {
+//	__disable_irq();
+//	LL_LPUART_Disable(LPUART1);
+//	LL_LPUART_DisableIT_RXNE(LPUART1);
 	LL_I2C_HandleTransfer(i2c_context->i2c, address, LL_I2C_ADDRSLAVE_7BIT, len,
 				LL_I2C_MODE_AUTOEND, LL_I2C_GENERATE_START_READ);
 	int i = 0;
@@ -60,5 +71,8 @@ int i2c_receive(uint8_t address, uint8_t *buffer, int len)
 	if (len != i) {
 		return I2C_ERROR_RX_INCOMPLETE;
 	}
+//	__enable_irq();
+//	LL_LPUART_Enable(LPUART1);
+//	LL_LPUART_EnableIT_RXNE(LPUART1);
 	return I2C_OK; // TODO error detection
 }

fw/Core/Src/main.c

@@ -231,6 +231,29 @@ int main(void)
   /* Enter the main loop */
   while (1)
   {
+	  if (lpuart1_rx_done == 1)
+	  {
+	  /* Process the message */
+		  if (lpuart1_rx_message_too_long)
+		  {
+			  /* Do nothing, just delete the buffer and set the flag back to zero*/
+			  lpuart1_rx_message_too_long = 0;
+		  } else
+		  {
+			  /* Process the message:
+			   * message is stored in modbus_buffer[], no copying necessary;
+			   * but we need to make sure that modbus_buffer[] will not be used while
+			   * processing the message: this can be done by disabling RX interrupt */
+			  LL_LPUART_DisableIT_RXNE(LPUART1);
+			  modbus_slave_process_msg(modbus_buffer, lpuart1_rx_message_len);
+			  /* Reset the RX DONE flag */
+			  lpuart1_rx_done = 0;
+			  LL_LPUART_EnableIT_RXNE(LPUART1);
+		  }
+		  /* Reset the RX DONE flag */
+		  lpuart1_rx_done = 0;
+	  }
+
 	  /* It is time for measurement */
 	  if (tim21_elapsed_period == 1)
 	  {

fw/Core/Src/stm32l0xx_it.c

@@ -45,6 +45,8 @@
 /* USER CODE BEGIN PV */
 uint16_t lpuart1_rx_message_index = 0;
 uint16_t lpuart1_rx_message_len = 0;
+uint8_t lpuart1_rx_done = 0;
+uint8_t lpuart1_rx_message_too_long = 0;
 
 uint8_t tim21_elapsed_period = 0;
 /* USER CODE END PV */
@@ -183,18 +185,11 @@ void LPUART1_IRQHandler(void)
 		/* Reset the buffer index */
 		lpuart1_rx_message_len = lpuart1_rx_message_index;
 		lpuart1_rx_message_index = 0;
+		lpuart1_rx_done = 1;
 		if (lpuart1_rx_message_len > MODBUS_MAX_RTU_FRAME_SIZE)
 		{
-			/* message too long, ignore */
-			return;
+			lpuart1_rx_message_too_long = 1;
 		}
-		/* Process the message:
-		* message is stored in modbus_buffer[], no copying necessary;
-		* but we need to make sure that modbus_buffer[] will not be used while
-		* processing the message: this can be done by disabling RX interrupt */
-		LL_LPUART_DisableIT_RXNE(LPUART1);
-		modbus_slave_process_msg(modbus_buffer, lpuart1_rx_message_len);
-		LL_LPUART_EnableIT_RXNE(LPUART1);
 	}
   /* USER CODE END LPUART1_IRQn 1 */
 }

tests/minimalmodbus_test.py

@@ -10,7 +10,7 @@ instrument.serial.baudrate = 115200
 instrument.serial.bytesize = 8
 instrument.serial.parity   = serial.PARITY_EVEN
 instrument.serial.stopbits = 1
-instrument.serial.timeout  = 0.05          # seconds
+instrument.serial.timeout  = 0.1          # seconds
 instrument.mode = minimalmodbus.MODE_RTU   # rtu or ascii mode
 instrument.clear_buffers_before_each_transaction = True