Hello to all. I am using SAME70.
For the protocol with variable packet length (MODBUS), you need to know how many bytes are read through the DMA channel to start the timeout.
I tried to determine the number of bytes read hrough the XDMAC registers (XDMAC_CDA, DMAC_CUBC).
Until the entire buffer is filled (256 bytes), the value of the registers does not change.
Is this a feature of SAME70?
As long as one option remains: Tx channel through DMA, Rx channel - by interruption UART_SR_RXRDY the register UART_RHR is read with the start of the timeout.
Who managed to use the XDMAC registers to determine the number of bytes read, tell me how to do this.