Re: [rtl] rt_com speed problems

[Richard Reeve <r.e.reeve@stir.ac.uk>]

Hi,

This is just to thank everyone and tell anybody else who experiences my
symptoms what the problem was. I was experiencing delays in multiple
independent small serial reads which I attributed to some latency in the
interrupts coming from the serial port. What I didn't realise is that
the serial chip has a 14 byte fifo buffer on it, which by default on the
version of rt_com I have (came with rtl 3.0) waits for 8 bytes to enter
the buffer before sending an interrupt (or for a timeout, which was the
delay I experienced).

As Jens suggested I had this input fifo switched on. Switching it off is
easy, changing the FIFO_TRIGGER #define in rt_comP.h - indeed you can
even extend it to the full 14 bytes before an interrupt if packets you
are receiving are much bigger than that I guess.

Thanks for all your help,

Cheers,

Richard Reeve