I've got a few Atmel AT89C55 chips. Some are DIP40 (AT89C55WD) and some are PLCC44 (AT89C55). If I wire up a PLCC socket to a DIP Socket with the corresponding pins from the PLCC to the right pins on the DIP, will it program ok and work the same as the DIP chips? I was told by someone that it wouldn't work, but I don't see why not. Thanks.
Yes, I realize that pin #x on plcc isn't necessarily the same pin # on dip and that there are a few n/c pins on the plcc package. I have the datasheets on both chips so I can map each pin based on what it's name / function is. So, that will work? Cool.
Yeah, it'd work because semiconductor companies are cheap. WHy would they spend money to make different masks for the same silicon die just because it's in a different package? They just use the same silicon die and "can" it differently, so all pins are identical across different packages and unused pins are just N/C.
Not all. I've seen several AVR's that have extra pins on PLCC or MLF packages that don't exist on their dip counter parts. Mostly it's Xtal or auxiliary functions like ADC and VREF signals that would otherwise share I/O pins moved to dedicated pins to free up some general purpose I/O this is easy enough to do with OTP fuses.