the developer of FreeRTOS who made the Demo application said in the serial.c about the implemented ISR, that there Implementation of the ISR is not an efficient implementation.
they rocommended the DMA or a RAM ring Buffer.
i implement a ring buffer, and every time a siganl is received in the RS232, the ISR will be called and write the new byte in this ring buffer.
now my question, what is the advantage of the ring buffer, if every time the received byte will trigger an interrupt.
it can be send through a queue too. or it will take more time because the API-call of xQueueSendFromISR.