On Friday 26 Sep 2003 12:17 am, you wrote:
> I am having a little trouble with a bit-bashed RECEIVE uart routine for
> PIC18F252. (Code is written in Hi-Tech C). Baud rate is 19200, Crystal is
> 16 MHz. (The hardware UART is already dedicated and I need a second port)
>
> The start bit is being detected by INT0 and then a getch() routine is being
> called to sample the incoming bits.
>
> It seems the Hi-Tech compiler saves all registers to be used in any code
> called from the interrupt and it appears that at present 100 cycles latency
> is occurring.
>
> Do I need to move the getch() routine into the interrupt handler ? or a
> better way of doing this ?
>

Bit bashing is such a hardware intimate function that IMHO you really should
be using assembler  for it.

Ian

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