On Thu, 12 Jun 2008 13:38:09 -0300, "Alexandre Guimar=E3es" said: > Can you explain better how to do it with 2x sampling ? I have always > used 3 times and it works because it is able to detect the start bit in > at > least in the first third part of the start bit. How can you detect the > start > bit and take the samples consistently with 2x the baud rate ?? Hi Alexandre, You caused me to look :) I used 4x sampling and got 9600 baud with 14MHz xtal. That is the method I show in the LCDterm: http://bobblick.com/techref/projects/lcdterm/lcdterm.html When I have done 2x sampling I could do 9600 baud with slower xtal but it is definitely less robust. The method was to set up a timer interrupt 19200 per second. Look for a start bit at the beginning of the interrupt routine, process incoming bits every 2 interrupts after that but process the incoming bits at the end of the timer interrupt, after the send routine and buffer routines. So there is less consistency in where the bit is captured but there is enough of a delay that if the start bit is detected at the very beginning you still get some margin. Cheerful regards, Bob -- = http://www.fastmail.fm - One of many happy users: http://www.fastmail.fm/docs/quotes.html -- = http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist