Ok, so I'm a rookie. I finally got timer0 and timer1 to go last night on mpsim. I made two mistakes. First, I tried to get rid of all the warnings when I ran mpasm. As a result, I set all my register locations to 7 bits. This confused mpsim, since it likes all 8 bits. Second, I had the order of the registers mixed up for bank 1. I had the option location in the wrong place. Now, I only need to get the timer1 interrupts working. Hopefully, I won't make so many stupid mistakes this time. I didn't get any replies on my initial message. I hope that the mail is getting through. I guess since it is summertime that everyone is out having fun! Gotta go, Derrick Early, the rookie