Last year I owned some Hardware with a Philips 80C552 MCU equipped, and I figured out two more devices.

One is a Coin counter with display, and I’ve seen the time always starts at 7:40 so I figured out that the M48T Timekeeper (In German we say “Tick-Tack-Stein”) was not working. With some tutorials I was able to mill the M48T and solder a new battery on.

At next the Coin counter shows not the correct currency, so at that point I decided to dig into the 80C51 development.

I dumped the ROMs and I look at the available 80C51 debugger/disassemblers etc. but none of them would fit fully the 80C552. So, I decided to create an own listing generator and debugger.

The app is written in C# .Net and WPF and is here available: https://github.com/mr-sven/Sim80C51

In the end I found the memory address where the index of the language table is stored, and I changed it to the correct currency.