Re: The cable to the wp 34s Message #3 Posted by Marcus von Cube, Germany on 3 May 2012, 5:33 p.m., in response to message #1 by JosefJ
Josef, one of my units brings out the three lines rxd, txd, and gnd to a 2mm stereo jack, borrowed from a TI "black" cable. You will need the 3.3V cable from FTDI, it should work out of the box.
RESET is no problem, the calculator has a hidden button on the back under a hole near the special connector and the batteries. For ERASE, you need to connect the erase bin on the connector to the 3V supply while the processor is doing something. You can force this by pressing and holding the ON key which will forcibly wake up the processor. If you need them I can send you the schematics of the 20b from the SDK. It's the same for the 30b.
If you open the calculator, add the crystal and its two caps as well as the IR diode and resistor. You will not regret it if you can get hold of an IR printer from HP. :-)
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