Help to identify a mice microcontroller

[powermax]

Hello crews,

I stumbled upon a firmware dump from a MCU resided in an old Apple ADB mice. I'd like to know the precise MCU architecture to be able to disassembly and analyze the device.

The part number is LSC84488P. The IC package shows Motorola and Logitech logos. I therefore assume that could be a custom part Motorola manufactured for Logitech.

The MCU is resided in a 28-pin DIP package.

That's how the device look like under the hood:



The firmwares dump is located here:

http://www.bitsavers.org/pdf/apple/adb/Apple/A9M0331/

Both *.bin dumps are 2KB big. The first 64 bytes are filled with 0xFF.

I don't know who and how made these dumps. That's why I'm asking here.

Any suggestions what kind of MCU it can be?

Best regards
Max

[CPUShack]

Would suspect 68HC05 type
mask is likely 8JG2 but cant trace that one down

[powermax]

Thanks a lot!

If that's 68HC05 one, where the reset vector is expected to be located?

[powermax]

It looks like the reset vector is located at 0x7FE.
The ROM dump v3.0 reveals an internal memory map very similar to that of MC6805P2 where the user ROM starts at offset 0x3C0.