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Sharp's graphing calculator PC software and link cables are hard to find these days so I thought I'd have a go at writing my own. I've had to do a lot of reverse engineering and there's still a long way to go but it feels like I'm on the right track.

Ben Ryves

@benryves.com

The intention is to support the EL-9400, 9450, 9600, 9900 and 9950. The first three use a proprietary link protocol and special cable, but I've managed to make it mostly work with TI's "black link" serial cable. The last two are different but a straight-through serial cable seems to work.

14/9/26, 2:06 pm0 reposts2 likes

Ben Ryves

@benryves.com

14 Sept

The black link code was mostly robust but would fail during long transfers (e.g. backups) after 20KB or so due to missing level transitions. Stuck SetPriorityClass(GetCurrentProcess(), REALTIME_PRIORITY_CLASS) in the code and it now works almost every time. Will still need to design a proper cable!