----- Original Message ----- From: "Jennifer Loiacono" To: Sent: Wednesday, January 23, 2002 12:35 PM Subject: [PIC]: PIC18 USART RX Data Corruption > Jennifer Loiacono > President > Automaton Engineering, Inc. > P.O. Box 10282 > Brooksville, FL 34603When receiving serial data on the PIC18C442, the value > is not reflected correctly in the RCREG reception register. However, the > signal on the receiving PIC is perfect in terms of timing and accuracy. > Despite accurate signal levels, debugging RCREG immediately after data is > received reveals that the byte seems to flip back and forth. > > e.g., a byte equal to 4 (dec) will oscillate between 4 and 32. A byte equal > to 1 will oscillate between 1 and 128, etc. > > Again, this value is being read immediately after reception (triggered by RX > interrupt), so it is highly unlikely that program code could be altering the > register after reception. > > Has anyone seen a problem like this before, or perhaps have any ideas as to > its cause? I have been stumped on this for a while, so ANY help would be > greatly appreciated! It usually happens when the serial data is not in the right form before it hits the PIC pin (wrong voltage levels, skewed pulses, parity bit mismatch...): where is it coming from? Straight from a PC port? From an optocoupler? from a rf receiver? Need more info. /\/\/\/*=Martin -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics