38400 should be easily done, cut all the delays in half =P maybe even 115200 but that would need like rewriting the whole code.. -andrew ----- Original Message ----- From: "Andy Shaw" To: Sent: Tuesday, March 25, 2003 6:40 PM Subject: [PIC]: Max bit bang serial on 4Mhz 16F876 > Folks, > Before I go off and waste a bunch of time trying to do the impossible (but > hey it may be fun), does anyone have any advice on what is the fastest half > duplex rs323 comms I can expect to get using software only on a 4MHz 16f876 > (using a resonator not a crystal)? > > I'm currently using the code created by Andy N1YEW and posted on piclist.com > and have this working fine at 19200 baud, but if possible I would like to > run a little faster. I know I should probably be using the built in hardware > but the board layout (not mine) will not allow it. I could also switch to a > higher speed but again I would like to avoid changes to the board. The way > things are I can probably dedicate the entire cpu to the serial code while > transmitting/receiving with the exception of a TMR0 roll over interrupt that > has been coded with minimal register save and just a simple increment of a > counter (approx 5 instructions long), the interrupt occurs every 65535 > instructions (TMR0 is using divide by 256 pre-scaler). > > Thanks for any help > > Andy > > -- > http://www.piclist.com hint: The PICList is archived three different > ways. See http://www.piclist.com/#archives for details. > -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.