At 04:00 PM 5/2/00 +1000, David Huisman wrote:
>Hi all,
>
>Has anyone here created a second software UART on the PIC16C73.
>I would like to have 2 ports simultaneously operating.
>The requirement only needs 1/2 duplex but I want to be able to receive 19200
>Baud via the on-board hardware UART simultaneously to 9600 Baud on the Bit
>bashed port.

This may be floating around on the net somewhere.  I'd check Mchips web
site for ASM versions of a bit banged uart.

I think the only thing you really have to worry about with your solution is
your 19200 code interrupting and causing timing skew in your software uart.
 The key here, as is always the case, is to keep your hardware uart
interrupt handler short and sweet.  Push the byte into a FIFO, clear
interrupts and get out of dodge.  Using the TMR1 for timing the software
uart is a good idea as this keeps your max latency to whatever length your
19200 int. routine is (plus latency).  I wouldn't try this with anything
less than a ~4Mhz PIC.

Good luck.



Erik Reikes
Senior Software Engineer
Xsilogy, Inc.

ereikes@xsilogy.com
ph : (858) 535-5113
fax : (858) 535-5163
cell : (858) 663-1206