Background information:
There are 2 versions of the 9860gII calculator, one with a SD-card connection and one without.
I bought the cheaper one and regret it (I want more storage), but I found out that it's very easy to add SD-card functionality this calculator.
Both calculators have the same CPU, PCB, firmware and case. actually the only difference is the colour and the SD-card slot.
And the SD-card slot is just a small PCB with some resistors and a clip to hold the card. It's connected to the main PCB with a ribbon cable.
^^I think they are just pull up resistors.
Technical information:
My calculator has a SuperH-3 RISC CPU, 1.5MB flash and 61kB of ram. It probably runs at 122MHz (that's what an overclocking-app says)
^I assume it's something like SH7705 or SH7706
On the PCB of the calculator there are 12 little pieces of exposed copper, exactly where the ribbon cable of the sd card should connect.
The SuperH chip has 12 GPIO pins... Probably that's what connects to the SD-card via SPI or so.
The only thing I have to do is make this SD-card-PCB, get a ribbon cable and solder the thing to my calculator.
To illustrate what I mean here is an equivalent thing for an arduino: (but I need this for a SuperH, not AVR)
My problem:
Although it should be an easy project but I don't know how to find out what pin on the PCB corresponds to what pin of the memory card. <<here's where I need help
I have found a pinout on http://datasheetdir.com/ but I don't know which of the pins are used for GPIO, so I still can't tell how to connect them.
The chip is not as popular as AVR or PIC when it comes to finding how to connect a SD card to it.
The CPU-chip is covered with some kind of black epoxy-like polymer.
I don't have advanced equipment, just the basics tools like a multimeter and soldering iron (the tip is small enough for this job).
Notes:
The original PCB uses SMT resistors but there is enough room for through hole ones, it's in a big enclosure.
Everything is big enough to be human solderable.
I know that even a noob could do this if he knows which pin goes to which.
Thanks in advance.