stm32/uart: Handle correctly the char overrun case of RXNE=0 and ORE=1.

dpgeorge · dpgeorge · commit 7b5bf5f6fda0 · 2019-04-01T13:40:35.000+11:00
Fixes issue micropython#3375.
diff --git a/ports/stm32/uart.c b/ports/stm32/uart.c
@@ -745,6 +745,16 @@ void uart_irq_handler(mp_uint_t uart_id) {
             }
         }
     }
+    // If RXNE is clear but ORE set then clear the ORE flag (it's tied to RXNE IRQ)
+    #if defined(STM32F4)
+    else if (self->uartx->SR & USART_SR_ORE) {
+        (void)self->uartx->DR;
+    }
+    #else
+    else if (self->uartx->ISR & USART_ISR_ORE) {
+        self->uartx->ICR = USART_ICR_ORECF;
+    }
+    #endif
 
     // Set user IRQ flags
     self->mp_irq_flags = 0;

Original file line number	Diff line number	Diff line change
`@@ -745,6 +745,16 @@ void uart_irq_handler(mp_uint_t uart_id) {`
`745`	`745`	`}`
`746`	`746`	`}`
`747`	`747`	`}`
	`748`	`+ // If RXNE is clear but ORE set then clear the ORE flag (it's tied to RXNE IRQ)`
	`749`	`+ #if defined(STM32F4)`
	`750`	`+ else if (self->uartx->SR & USART_SR_ORE) {`
	`751`	`+ (void)self->uartx->DR;`
	`752`	`+ }`
	`753`	`+ #else`
	`754`	`+ else if (self->uartx->ISR & USART_ISR_ORE) {`
	`755`	`+ self->uartx->ICR = USART_ICR_ORECF;`
	`756`	`+ }`
	`757`	`+ #endif`
`748`	`758`
`749`	`759`	`// Set user IRQ flags`
`750`	`760`	`self->mp_irq_flags = 0;`