STM32: Serial - do no clear RXNE flag

LMESTM · LMESTM · commit 85711eb09e1a · 2017-07-17T08:46:00.000+02:00
The RXNE flag is getting cleared when reading Data Register so it should
not be cleared here. Especially in case of high data rate, another byte of
data could have received during irq_handler call and clearing the flag
would read and discard this data which would be lost for application.
diff --git a/targets/TARGET_STM/TARGET_STM32F0/serial_device.c b/targets/TARGET_STM/TARGET_STM32F0/serial_device.c
@@ -273,8 +273,7 @@ static void uart_irq(int id)
         if (__HAL_UART_GET_FLAG(huart, UART_FLAG_RXNE) != RESET) {
             if (__HAL_UART_GET_IT(huart, UART_IT_RXNE) != RESET) {
                 irq_handler(serial_irq_ids[id], RxIrq);
-                volatile uint32_t tmpval = huart->Instance->RDR; // Clear RXNE flag
-                UNUSED(tmpval);
+                /*  Flag has been cleared when reading the content */
             }
         }
         if (__HAL_UART_GET_FLAG(huart, UART_FLAG_ORE) != RESET) {
diff --git a/targets/TARGET_STM/TARGET_STM32F1/serial_device.c b/targets/TARGET_STM/TARGET_STM32F1/serial_device.c
@@ -168,7 +168,7 @@ static void uart_irq(int id)
         if (__HAL_UART_GET_FLAG(huart, UART_FLAG_RXNE) != RESET) {
             if (__HAL_UART_GET_IT_SOURCE(huart, UART_IT_RXNE) != RESET) {
                 irq_handler(serial_irq_ids[id], RxIrq);
-                __HAL_UART_CLEAR_FLAG(huart, UART_FLAG_RXNE);
+                /*  Flag has been cleared when reading the content */
             }
         }
         if (__HAL_UART_GET_FLAG(huart, UART_FLAG_ORE) != RESET) {
diff --git a/targets/TARGET_STM/TARGET_STM32F2/serial_device.c b/targets/TARGET_STM/TARGET_STM32F2/serial_device.c
@@ -255,7 +255,7 @@ static void uart_irq(int id)
         if (__HAL_UART_GET_FLAG(huart, UART_FLAG_RXNE) != RESET) {
             if (__HAL_UART_GET_IT_SOURCE(huart, UART_IT_RXNE) != RESET) {
                 irq_handler(serial_irq_ids[id], RxIrq);
-                __HAL_UART_CLEAR_FLAG(huart, UART_FLAG_RXNE);
+                /*  Flag has been cleared when reading the content */
             }
         }
         if (__HAL_UART_GET_FLAG(huart, UART_FLAG_ORE) != RESET) {
diff --git a/targets/TARGET_STM/TARGET_STM32F3/serial_device.c b/targets/TARGET_STM/TARGET_STM32F3/serial_device.c
@@ -218,9 +218,8 @@ static void uart_irq(int id)
         }
         if (__HAL_UART_GET_FLAG(huart, UART_FLAG_RXNE) != RESET) {
             if (__HAL_UART_GET_IT(huart, UART_IT_RXNE) != RESET) {
-            irq_handler(serial_irq_ids[id], RxIrq);
-                volatile uint32_t tmpval = huart->Instance->RDR; // Clear RXNE flag
-                UNUSED(tmpval);
+                irq_handler(serial_irq_ids[id], RxIrq);
+                /*  Flag has been cleared when reading the content */
             }
         }
         if (__HAL_UART_GET_FLAG(huart, UART_FLAG_ORE) != RESET) {
diff --git a/targets/TARGET_STM/TARGET_STM32F4/serial_device.c b/targets/TARGET_STM/TARGET_STM32F4/serial_device.c
@@ -282,7 +282,7 @@ static void uart_irq(int id)
         if (__HAL_UART_GET_FLAG(huart, UART_FLAG_RXNE) != RESET) {
             if (__HAL_UART_GET_IT_SOURCE(huart, UART_IT_RXNE) != RESET) {
                 irq_handler(serial_irq_ids[id], RxIrq);
-                __HAL_UART_CLEAR_FLAG(huart, UART_FLAG_RXNE);
+                /*  Flag has been cleared when reading the content */
             }
         }
         if (__HAL_UART_GET_FLAG(huart, UART_FLAG_ORE) != RESET) {
diff --git a/targets/TARGET_STM/TARGET_STM32F7/serial_device.c b/targets/TARGET_STM/TARGET_STM32F7/serial_device.c
@@ -247,7 +247,7 @@ static void uart_irq(int id)
         if (__HAL_UART_GET_FLAG(huart, UART_FLAG_RXNE) != RESET) {
             if (__HAL_UART_GET_IT(huart, UART_IT_RXNE) != RESET) {
                 irq_handler(serial_irq_ids[id], RxIrq);
-                volatile uint32_t tmpval = huart->Instance->RDR; // Clear RXNE
+                /*  Flag has been cleared when reading the content */
             }
         }
         if (__HAL_UART_GET_FLAG(huart, UART_FLAG_ORE) != RESET) {
diff --git a/targets/TARGET_STM/TARGET_STM32L0/serial_device.c b/targets/TARGET_STM/TARGET_STM32L0/serial_device.c
@@ -210,7 +210,7 @@ static void uart_irq(int id)
         if (__HAL_UART_GET_FLAG(huart, UART_FLAG_RXNE) != RESET) {
             if (__HAL_UART_GET_IT(huart, UART_IT_RXNE) != RESET) {
                 irq_handler(serial_irq_ids[id], RxIrq);
-                volatile uint32_t tmpval = huart->Instance->RDR; // Clear RXNE flag
+                /*  Flag has been cleared when reading the content */
             }
         }
         if (__HAL_UART_GET_FLAG(huart, UART_FLAG_ORE) != RESET) {
diff --git a/targets/TARGET_STM/TARGET_STM32L1/serial_device.c b/targets/TARGET_STM/TARGET_STM32L1/serial_device.c
@@ -199,7 +199,7 @@ static void uart_irq(int id)
         if (__HAL_UART_GET_FLAG(huart, UART_FLAG_RXNE) != RESET) {
             if (__HAL_UART_GET_IT_SOURCE(huart, UART_IT_RXNE) != RESET) {
                 irq_handler(serial_irq_ids[id], RxIrq);
-                __HAL_UART_CLEAR_FLAG(huart, UART_FLAG_RXNE);
+                /*  Flag has been cleared when reading the content */
             }
         }
         if (__HAL_UART_GET_FLAG(huart, UART_FLAG_ORE) != RESET) {
diff --git a/targets/TARGET_STM/TARGET_STM32L4/serial_device.c b/targets/TARGET_STM/TARGET_STM32L4/serial_device.c
@@ -225,8 +225,8 @@ static void uart_irq(int id)
         }
         if (__HAL_UART_GET_FLAG(huart, UART_FLAG_RXNE) != RESET) {
             if (__HAL_UART_GET_IT(huart, UART_IT_RXNE) != RESET) {
-            irq_handler(serial_irq_ids[id], RxIrq);
-                __HAL_UART_CLEAR_FLAG(huart, UART_FLAG_RXNE);
+                irq_handler(serial_irq_ids[id], RxIrq);
+                /*  Flag has been cleared when reading the content */
             }
         }
         if (__HAL_UART_GET_FLAG(huart, UART_FLAG_ORE) != RESET) {

Original file line number	Diff line number	Diff line change
`@@ -273,8 +273,7 @@ static void uart_irq(int id)`
`273`	`273`	`if (__HAL_UART_GET_FLAG(huart, UART_FLAG_RXNE) != RESET) {`
`274`	`274`	`if (__HAL_UART_GET_IT(huart, UART_IT_RXNE) != RESET) {`
`275`	`275`	`irq_handler(serial_irq_ids[id], RxIrq);`
`276`		`- volatile uint32_t tmpval = huart->Instance->RDR; // Clear RXNE flag`
`277`		`- UNUSED(tmpval);`
	`276`	`+ /* Flag has been cleared when reading the content */`
`278`	`277`	`}`
`279`	`278`	`}`
`280`	`279`	`if (__HAL_UART_GET_FLAG(huart, UART_FLAG_ORE) != RESET) {`
Original file line number	Diff line number	Diff line change
`@@ -168,7 +168,7 @@ static void uart_irq(int id)`
`168`	`168`	`if (__HAL_UART_GET_FLAG(huart, UART_FLAG_RXNE) != RESET) {`
`169`	`169`	`if (__HAL_UART_GET_IT_SOURCE(huart, UART_IT_RXNE) != RESET) {`
`170`	`170`	`irq_handler(serial_irq_ids[id], RxIrq);`
`171`		`- __HAL_UART_CLEAR_FLAG(huart, UART_FLAG_RXNE);`
	`171`	`+ /* Flag has been cleared when reading the content */`
`172`	`172`	`}`
`173`	`173`	`}`
`174`	`174`	`if (__HAL_UART_GET_FLAG(huart, UART_FLAG_ORE) != RESET) {`
Original file line number	Diff line number	Diff line change
`@@ -255,7 +255,7 @@ static void uart_irq(int id)`
`255`	`255`	`if (__HAL_UART_GET_FLAG(huart, UART_FLAG_RXNE) != RESET) {`
`256`	`256`	`if (__HAL_UART_GET_IT_SOURCE(huart, UART_IT_RXNE) != RESET) {`
`257`	`257`	`irq_handler(serial_irq_ids[id], RxIrq);`
`258`		`- __HAL_UART_CLEAR_FLAG(huart, UART_FLAG_RXNE);`
	`258`	`+ /* Flag has been cleared when reading the content */`
`259`	`259`	`}`
`260`	`260`	`}`
`261`	`261`	`if (__HAL_UART_GET_FLAG(huart, UART_FLAG_ORE) != RESET) {`
Original file line number	Diff line number	Diff line change
`@@ -218,9 +218,8 @@ static void uart_irq(int id)`
`218`	`218`	`}`
`219`	`219`	`if (__HAL_UART_GET_FLAG(huart, UART_FLAG_RXNE) != RESET) {`
`220`	`220`	`if (__HAL_UART_GET_IT(huart, UART_IT_RXNE) != RESET) {`
`221`		`- irq_handler(serial_irq_ids[id], RxIrq);`
`222`		`- volatile uint32_t tmpval = huart->Instance->RDR; // Clear RXNE flag`
`223`		`- UNUSED(tmpval);`
	`221`	`+ irq_handler(serial_irq_ids[id], RxIrq);`
	`222`	`+ /* Flag has been cleared when reading the content */`
`224`	`223`	`}`
`225`	`224`	`}`
`226`	`225`	`if (__HAL_UART_GET_FLAG(huart, UART_FLAG_ORE) != RESET) {`
Original file line number	Diff line number	Diff line change
`@@ -282,7 +282,7 @@ static void uart_irq(int id)`
`282`	`282`	`if (__HAL_UART_GET_FLAG(huart, UART_FLAG_RXNE) != RESET) {`
`283`	`283`	`if (__HAL_UART_GET_IT_SOURCE(huart, UART_IT_RXNE) != RESET) {`
`284`	`284`	`irq_handler(serial_irq_ids[id], RxIrq);`
`285`		`- __HAL_UART_CLEAR_FLAG(huart, UART_FLAG_RXNE);`
	`285`	`+ /* Flag has been cleared when reading the content */`
`286`	`286`	`}`
`287`	`287`	`}`
`288`	`288`	`if (__HAL_UART_GET_FLAG(huart, UART_FLAG_ORE) != RESET) {`
Original file line number	Diff line number	Diff line change
`@@ -247,7 +247,7 @@ static void uart_irq(int id)`
`247`	`247`	`if (__HAL_UART_GET_FLAG(huart, UART_FLAG_RXNE) != RESET) {`
`248`	`248`	`if (__HAL_UART_GET_IT(huart, UART_IT_RXNE) != RESET) {`
`249`	`249`	`irq_handler(serial_irq_ids[id], RxIrq);`
`250`		`- volatile uint32_t tmpval = huart->Instance->RDR; // Clear RXNE`
	`250`	`+ /* Flag has been cleared when reading the content */`
`251`	`251`	`}`
`252`	`252`	`}`
`253`	`253`	`if (__HAL_UART_GET_FLAG(huart, UART_FLAG_ORE) != RESET) {`
Original file line number	Diff line number	Diff line change
`@@ -210,7 +210,7 @@ static void uart_irq(int id)`
`210`	`210`	`if (__HAL_UART_GET_FLAG(huart, UART_FLAG_RXNE) != RESET) {`
`211`	`211`	`if (__HAL_UART_GET_IT(huart, UART_IT_RXNE) != RESET) {`
`212`	`212`	`irq_handler(serial_irq_ids[id], RxIrq);`
`213`		`- volatile uint32_t tmpval = huart->Instance->RDR; // Clear RXNE flag`
	`213`	`+ /* Flag has been cleared when reading the content */`
`214`	`214`	`}`
`215`	`215`	`}`
`216`	`216`	`if (__HAL_UART_GET_FLAG(huart, UART_FLAG_ORE) != RESET) {`
Original file line number	Diff line number	Diff line change
`@@ -199,7 +199,7 @@ static void uart_irq(int id)`
`199`	`199`	`if (__HAL_UART_GET_FLAG(huart, UART_FLAG_RXNE) != RESET) {`
`200`	`200`	`if (__HAL_UART_GET_IT_SOURCE(huart, UART_IT_RXNE) != RESET) {`
`201`	`201`	`irq_handler(serial_irq_ids[id], RxIrq);`
`202`		`- __HAL_UART_CLEAR_FLAG(huart, UART_FLAG_RXNE);`
	`202`	`+ /* Flag has been cleared when reading the content */`
`203`	`203`	`}`
`204`	`204`	`}`
`205`	`205`	`if (__HAL_UART_GET_FLAG(huart, UART_FLAG_ORE) != RESET) {`
Original file line number	Diff line number	Diff line change
`@@ -225,8 +225,8 @@ static void uart_irq(int id)`
`225`	`225`	`}`
`226`	`226`	`if (__HAL_UART_GET_FLAG(huart, UART_FLAG_RXNE) != RESET) {`
`227`	`227`	`if (__HAL_UART_GET_IT(huart, UART_IT_RXNE) != RESET) {`
`228`		`- irq_handler(serial_irq_ids[id], RxIrq);`
`229`		`- __HAL_UART_CLEAR_FLAG(huart, UART_FLAG_RXNE);`
	`228`	`+ irq_handler(serial_irq_ids[id], RxIrq);`
	`229`	`+ /* Flag has been cleared when reading the content */`
`230`	`230`	`}`
`231`	`231`	`}`
`232`	`232`	`if (__HAL_UART_GET_FLAG(huart, UART_FLAG_ORE) != RESET) {`