Wednesday, 14 July 2010

Psion II in on the act

I have been meaning to press my old Psion II LZ into service for a while. Now if you go way back in the blog you'll see that I was building a parallel port interface a while back for the Psion, but early tests revealed that it was painfully slow and also there were some bugs in the operation of the port, so I temporarily shelved that.

Having mastered RS232 on the PIC using JAL (which is just so good I had to order the book), this opened up another avenue, communicating serially with the Psion. So here we go, the Psion II is receiving the data stream from my 16F690 A/D device and selecting one of the 8 channels to display. I experimented with displaying a bar graph on the Psion LCD, but once again, the speed was against me. I fear I may need to look at some simple assembly to achieve that one.
Here's the full set-up with the Psion connected to the PIC via a (long) null modem cable, which would be spot on for connecting to my diagnostic system in the Toyota and taking readings up front in the driver's seat.

I'm keen now to try interfacing the Psion to the robotics SERIALLY, using a PIC 16F84/88 and a MAX232 to go from RS232 to general I/O, but with a bit of intelligence thrown in for good measure, things like command strings and so on.

Getting there!

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