I have a couple old gizmos that use the microcontroller Megawin MPC89E52A. I want to download the existing code, disassemble it, make my own changes and reprogram.
The datasheet seems pretty basic, but it does state that it's "fully compatible with industrial-standard 80C51 series microcontroller." The datasheet also states "8K bytes flash memory embedded for application program" which I believe means it can be reprogrammed based on the googling I've done so far.
There is a row of pins labeled R, T, I, G, and A which I traced to RXD, TXD, INT0, RESET, and EA. EA is described in the sheet as "EA must be kept at low to enable the device to fetch program code from external flash memory" which sounds promising.
I know nothing about 80C51 parts except that they are all over. I assume that there are lots of tools for them if I know where to look.
- do I have any chance of success with this particular part?
- If I can't reprogram it, can I at least download the existing code and would it be difficult to find a pin-compatible replacement? it's a QFP-44
- Assuming that reprogramming is possible, are the pins mentioned above the correct ones for this?
- What software tools for programming?
- Finally, what kind of a programmer do I need? Hopefully something usb is available, but I can make parallel or serial work.
Perhaps the most important question: Where's the best place to look for info on this?