Using a PIC18F4550 package for PIC18F2550 compiled code. Any issues?

[ScaleRobotics]

I am building a product I want to be compatible with the Experimenters Version of PBP3 for a 18F2550. However, the 2550's smallest package is a soic, and this needs to be small. The 18F4550 does come in a QFN, so I was looking at that as a possible replacement. I have done a few tests with Microchip's HID USB bootloader loaded on a 18F4550. It accepts hex files compiled for a 18F2550, and the few tests I did worked fine, operating the standard ports, and using Steve's (updated by Darrel) USB Demo program. I don't need to utilize any more pins than a 2550, I just need the smaller package. (It will always be programmed with the USB bootloader).

Does anyone see any issues with this setup?

Thanks,

Walter

[mackrackit]

Ground the leftover pins so they do not cause problems.

[Archangel]

Hi Walter,
You are probably going to be alright going that way, except for having more memory than you can access, I think if you went the other way it would put the hurt on you.

[Demon]

What does ADC have to do with USB?