On first debug session everything works fine. However on second and beyond session dma stop working.
Hardware: custom stm32l4p5cet based board, original ft232 uart bridge, stlink v2.
CubeMX settings: UART with DMA on RX and TX (RX in circular mode), Global interrupt enabled with priority 5.
Code:
Start DMA returning HAL_OK:
HAL_UART_Receive_DMA(&huart2, serial_data, 128);
Task to put data from uart in to message queue:
static uint16_t tail;
void serial_input_task(void *arg)
{
for (;;) {
uint16_t len = 128 - huart2.hdmarx->Instance->CNDTR;
while (len - tail) {
uint8_t tmp = serial_data[tail];
osMessageQueuePut(at_input_queue, (const void*) &tmp, 0, 0);
tail++;
if (tail >= 128)
tail = 0;
}
osDelay(1);
}
}
task to read message queue and process data:
static uint8_t at_serial_input[128];
void input_task(void *arg)
{
uint32_t count;
while (1) {
count = osMessageQueueGetCount(input_queue);
for (uint32_t i = 0; i < count; i++)
osMessageQueueGet(input_queue,(void*) &serial_input[i], 0, 0);
if (count)
input(serial_input, count); //handle raw data from uart
}
}
function input never get called, for testing purposes I added RxCpltCallback to light up led. Never get called or light up, even in first debug session.
void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{
HAL_GPIO_WritePin(LED2_GPIO_Port, LED2_Pin, GPIO_PIN_SET);
}
