Средства и методы разработки

__attribute__((used)) int _write(int fd, char *buf, int size)
{
    if (size <= 0) return 0;
    size_t sent = xStreamBufferSend( uart_tx_stream, buf, size, 0 );
    xTaskNotify(UART1_Task_Handler, 0x10, eSetBits);
    return sent;
}
........................................................................

 void UART1_task(void *pvParameters)
{
uint32_t notif_bits;
while (1)
{
   xTaskNotifyWait(0, 0x10,  & notif_bits, portMAX_DELAY);
   while (xStreamBufferBytesAvailable(uart_tx_stream) > 0){
     uint32_t len = xStreamBufferBytesAvailable(uart_tx_stream);
     if (len > 0) {
       uint8_t *dma_buf = pvPortMalloc(len);
       xStreamBufferReceive(uart_tx_stream, dma_buf, len, 0);
       DMA1_Channel4->CFGR &= ~DMA_CFG4_EN;
       DMA1->INTFCR = DMA_CTCIF4;
       DMA1_Channel4->MADDR = (uint32_t)dma_buf;
       DMA1_Channel4->CNTR = (uint16_t)len;
       DMA1_Channel4->CFGR |= DMA_CFG4_EN | DMA_CFG4_TCIE;
       do {
         xTaskNotifyWait(0, 0x08, & notif_bits, portMAX_DELAY);
       } while ((notif_bits & 0x08) == 0);
      vPortFree(dma_buf);
     }
   }
  }
}
.................................................................