Update uart driver for low power mode

Signed-off-by: fpr <[email protected]>

Author: fpr

cores/arduino/HardwareSerial.cpp

@@ -373,5 +373,6 @@ void HardwareSerial::setRx(PinName _rx) {
 void HardwareSerial::setTx(PinName _tx){
   _serial.pin_tx = _tx;
 }
+
 #endif // HAVE_HWSERIALx
 #endif // !NO_HWSERIAL

cores/arduino/HardwareSerial.h

@@ -124,6 +124,8 @@ class HardwareSerial : public Stream
     void setRx(PinName _rx);
     void setTx(PinName _tx);
 
+    friend class STM32LowPower;
+
     // Interrupt handlers
     static void _rx_complete_irq(serial_t* obj);
     static int _tx_complete_irq(serial_t* obj);

cores/arduino/stm32/uart.c

@@ -128,12 +128,20 @@ void uart_init(serial_t *obj)
 
   // Enable USART clock
   if(obj->uart == USART1) {
+#ifdef STM32L4xx
+    // Configure HSI as source clock for low power wakeup clock
+    __HAL_RCC_USART1_CONFIG(RCC_USART1CLKSOURCE_HSI);
+#endif
     __HAL_RCC_USART1_FORCE_RESET();
     __HAL_RCC_USART1_RELEASE_RESET();
     __HAL_RCC_USART1_CLK_ENABLE();
     obj->index = 0;
     obj->irq = USART1_IRQn;
   } else if(obj->uart == USART2) {
+#ifdef STM32L4xx
+    // Configure HSI as source clock for low power wakeup clock
+    __HAL_RCC_USART2_CONFIG(RCC_USART2CLKSOURCE_HSI);
+#endif
     __HAL_RCC_USART2_FORCE_RESET();
     __HAL_RCC_USART2_RELEASE_RESET();
     __HAL_RCC_USART2_CLK_ENABLE();
@@ -142,6 +150,10 @@ void uart_init(serial_t *obj)
   }
 #if defined(USART3_BASE)
   else if(obj->uart == USART3) {
+#ifdef STM32L4xx
+    // Configure HSI as source clock for low power wakeup clock
+    __HAL_RCC_USART3_CONFIG(RCC_USART3CLKSOURCE_HSI);
+#endif
     __HAL_RCC_USART3_FORCE_RESET();
     __HAL_RCC_USART3_RELEASE_RESET();
     __HAL_RCC_USART3_CLK_ENABLE();
@@ -151,6 +163,10 @@ void uart_init(serial_t *obj)
 #endif
 #if defined(UART4_BASE)
   else if(obj->uart == UART4) {
+#ifdef STM32L4xx
+    // Configure HSI as source clock for low power wakeup clock
+    __HAL_RCC_UART4_CONFIG(RCC_UART4CLKSOURCE_HSI);
+#endif
     __HAL_RCC_UART4_FORCE_RESET();
     __HAL_RCC_UART4_RELEASE_RESET();
     __HAL_RCC_UART4_CLK_ENABLE();
@@ -168,6 +184,10 @@ void uart_init(serial_t *obj)
 #endif
 #if defined(UART5_BASE)
   else if(obj->uart == UART5) {
+#ifdef STM32L4xx
+    // Configure HSI as source clock for low power wakeup clock
+    __HAL_RCC_UART5_CONFIG(RCC_UART5CLKSOURCE_HSI);
+#endif
     __HAL_RCC_UART5_FORCE_RESET();
     __HAL_RCC_UART5_RELEASE_RESET();
     __HAL_RCC_UART5_CLK_ENABLE();
@@ -284,6 +304,7 @@ void uart_init(serial_t *obj)
   huart->Init.Mode         = UART_MODE_TX_RX;
   huart->Init.HwFlowCtl    = UART_HWCONTROL_NONE;
   huart->Init.OverSampling = UART_OVERSAMPLING_16;
+  huart->AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;
   // huart->Init.OneBitSampling = UART_ONE_BIT_SAMPLE_DISABLE;
 
   if(HAL_UART_Init(huart) != HAL_OK) {
@@ -854,6 +875,19 @@ void UART10_IRQHandler(void)
 }
 #endif
 
+/**
+  * @brief  HAL UART Call Back
+  * @param  UART handler
+  * @retval None
+  */
+void HAL_UARTEx_WakeupCallback(UART_HandleTypeDef *huart)
+{
+  uint8_t index = uart_index(huart);
+  serial_t *obj = rx_callback_obj[index];
+
+  HAL_UART_Receive_IT(huart,  &(obj->recv), 1);
+}
+
 #ifdef __cplusplus
 }
 #endif