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Saturday, 17 January 2015

 HP30b Calculator JTAG Connector 

The HP30b is a repurposable calculator, but to do this you need either a serial cable or a JTAG connector. I have a JTAG adapter, so needed a hole in the calculator case for the connector.

A few minute on the milling machine and we have two neat holes in the back of the case:


That is for extra IO, probably ADC inputs.

JTAG connector:




 having proper holes is a lot easier when trying the JTAG out as the batteries are held in by the case and having to hold the battry in while doing other stuff was a pain. Next job is to make a serial connector from some pins and milled plastic. That will allow reflashing.

The Eclipse setup for the JTAG was a bit of a pain but looks to be close to working now. I have to erase the flash and get my code on the board before it will work properly I think, as the security bit is probably set in the processor chip.






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