On Sun, 2005-03-13 at 15:42 +0000, Matt Evans wrote: [...]
Yep, the case was discarded long ago. So this sounds interesting - I thought all units had the smartmedia slot. Mine certainly does - but I have the older psion5-style keyboard model. Does yours still have a smart/card/ slot on the right too?
Yes. I actually rather wanted the SMC socket, and the cold-flesh keyboard is pretty dire. I *suppose* it might be possible to solder on a third-party SMC socket but I don't think my soldering skills are up to it. Just have to make do with USB.
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Something that was unclear in your previous emails was the cable that you were using - it sounded like it was direct RS232 plug to a 3.5mm jack with no voltage conversion? This didn't work for me.
Ah, I thought you said it *did* work... hopefully I haven't buggered the UART.
I experimented with a voltmeter, and I'm seeing just under 5V on RX and TX coming from the E2, which matches what you said. Alas, I don't have a scope.
Hmm... TTL uses 0V for 0, 5V for 1. RS232 uses >+3V for 0 and <-3V for 1. Now, if the E2's UART is behaving sensibly, and is suitably buffered so that I haven't fried it, it might be possible to con it into responding to the RS232 signals by sending a suitably mutated signal. Basically, I'd need to send ~0x1B = 0xE4, with an inverted stop bit... but the E2 wouldn't be able to reply, because the TTL 0V signals that it's sending would be ignored by the PC's UART. Blast.
I could probably rig up a software UART through the parallel port, if I had one. (Shuttle box. I'm trying to scrounge up the appropriate header, but it's had work.)
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I don't know your level of electronics knowledge but if I can help just ask.
I'm mostly a software guy; I have some soldering skills, but they're not great. I can rig up a line driver on breadboard easily enough, but getting a 5V signal that's suitable non-floating might be an issue...
I actually have a ludicrous idea that might help; will report back later.