Hi, I built a small 68HC11A1 board about a year ago and recently dug it out from my junk box with intent of using it for a small robot. The problem is, that PCBug11 (on an old 486 computer) will not talk to it. I've tested my MAX232A circuit and it's working correctly. I checked the clock pin on the HC11 and it shows a correct frequency pulse. MODA and MODB are tied to ground (bootstrap mode). Vcc is correct. My crystal is 4.9157 mhz, and the baud rate I am using is 4800. I did this a year ago and the board connected via pcbug.
On my OScope I can see pcbug sending data on the TX line, but I get no response from the microcontroller.
I remember reading somewhere that the HC11 memory can become corrupt (usually by reset bounce) preventing it from operating correctly. I used the reset chip, so I know I dont have this problem, but could something else have corrupted the memory? Is there anything else I should check before it goes in the trash? I hate to trash it because I built the board from scratch, all point to point wiring :(
The error I get is "Communication Failure".
Thanks in advance, Tom