[Lazarus] SdpoSerial Tx and Rx buffers?

[Hans-Peter Diettrich]

José Mejuto schrieb:

> MS> Regarding sending, there still is a FiFo (usually some 4..64  Bytes ) in
> MS> the serial hardware (hundreds or thousands of bytes) and a software Fifo
> MS> in the OS driver. So the software can't tell when something has left the
> MS> serial port. For such deeply embedded issues  the specifics of the
> MS> driver and hardware needs to be considered
> 
> AFAIK the FIFO is in the receive, in sent the FIFOs are filled but
> function does not return until the hardware sends the last byte.

I'm not sure, but IMO a FIFO for outgoing data is used at best in a 
*synchronous* protocol, not in a UART. More likely synchronous I/O is 
done by DMA, not in code. But which nowadays hardware is capable of 
synchronous serial transmission at all?

DoDi