Hi all,

I was here a while back asking about the above referenced devices. I seem to have run into some new challenges and thought someone might have the info on this (I expect I'll contact Atmel after they're back from vacation next week).

I have a design based on the 8051 device. I have been prototyping with an 80C31 and it seems to run fine. I got a hold of some AT89C51RC and AT89C51RC2 devices from Atmel (larger on-chip FLASH and ERAM). I know that the RC2 device has some boot ROM addressing setup required as well 1 or 2 other features which makes it different from the standard 80C51.

I tried the RC version and "thought" I had it working. Now it doesn't (had thought it might have been due to some code I changed). I also thought I had the RC2 working as well (apparently not). With the RC or RC2 installed, I get somewhat erratic operation in the display (unexpected results, etc.). Most of this comes from a mem-mapped I/O device in the XDATA space. However, when I plug in the 80C31, everything seems to work fine.

I suspect this may be due to some timing issue and I plan to pull out my scope to check it out. However, I thought (and assumed) that the RC would be, and RC2 could be made, plug-in compatible with the 80C31 (especially by "flattening" the extra features of the RC2...not sure if any of that needs to be done with the RC version). Obviously, I'm missing something here.

Anyone have any good ideas about this?

Thanks much in advance and Happy New to all (Be safe and smart!!).

Cheers...Steph