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Calculators with Support of the 82240 IR-Printer
06-30-2014, 11:39 AM
Post: #27
RE: Calculators with Support of the 82240 IR-Printer
(06-27-2014 03:54 PM)Christoph Giesselink Wrote:  [... deleted ...]

The 3rd version is implemented in C and published under the GPL v2 inside Emu28 and Emu42 (file REDEYE.C). The implementation is also "interrupt driven". At every rising edge of the IR output pin the decoder is called. The timing is generated over the elapsed CPU cycles which is in reality the elaped time since the last IR signal rising edge. The implementation of the error correction is complete, in fact it can restore two missed bits.

[... deleted ...]

Ah, thank you, I had not seen these sources and I followed a different way than proposed in the HP docs (measuring the time between bursts) by sampling at regular intervals. Both strategies seem to work well. I hope to test my receiver also with an HP 28S soon and then put it into a nice casing. I am also looking for a cheap thermoprinter understanding ESC/POS (cash register) codes which would allow building a low cost HP 82240 replacement for hobby use (just for fun, no commercial background).
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RE: Calculators with Support of the 82240 IR-Printer - Martin Hepperle - 06-30-2014 11:39 AM



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