HP67 running

[PANAMATIK]

(05-29-2016 10:37 AM)teenix Wrote:  I wouldn't expect a PIC to have much trouble bit banging the serial data in on any input pin unless logic level conversion is required which would require an external buffer. I've written a few duplex RS-232 applications at 19200 baud using this approach. An edge detect interrupt could be used to frame incoming data bits and shift them into a buffer easily enough.

As always the devil is in the details, i.e.DATA line from CRC must be read with 180000 baud, and the line must be bidirectional. But I admit, that I not yet tried everything what bits can do with a PIC. And only recently I found the key for communicating from PIC to PIK (excuse the pun).

My question is, how many HP-67s need a new ACT for repair. And would their owners also repair the card reader if the ACT would be able to read/write cards?

Bernhard