This is the cassette player as fitted to some 450 fortwo and Roadsters.
Firstly we need to open the case to get to the chips. Remove the Torx 10 screw.
Lever and lift the cover from the back. Try not to bend it.
There are 4 Torx screws from the cassette mechanism. 2 at the front...
...1 at the rear top...
...and 1 on the rear side.
Carefully lift the cassette mechanism out of the chassis which has electrical connections at the back.
Now we can see all of the chips.
It's the big one that we are interested in. It's an MC68HC711KA2CFN4, a 68 pin microprocessor.
The pin out for the chip doesn't really give you any idea of what connections we need to use.
Luckily, we don't need to use that many connections. Here are the connections
required for reading the code using an Xprog 5.5.