In SX Microcontrollers, SX/B Compiler and SX-Key Tool, Zoot wrote:

but if you think that may be the problem, your most likely right :)

> Don't be so sure... I'm just naming things that could be suspect. I also would look to JonnyMac's comments -- given possible pauses between TX and RX from each device, it might be possible that a full byte is never sent while the SX is ready -- but since you don't have a long pause in the TX loop, I would think eventually it would send a byte while the RX is ready. I use both single-byte and the multi-byte buffered version of Jon's ISR serial code myself -- but that can look more complex than it is. As Jonny mentioned SERIN *waits* for the start bit of a byte (and could wait forever, hanging the program); the ISR version just receives the byte whenever it comes and stores it until the main program loop goes and checks to see if anything came in. In any case, it still seems like your setup should work, barring wiring/flashing/clock errors. If you keep having problems with this code, you could think about doing a small test/debug program that counts out milliseconds in a debug WATCH window -- that would at least tell you if you are downloading/running/clocking/debugging correctly with the SX-Key (if your clock speed is screwy you won't get an accurate count after a large number of milliseconds, and if the Key isn't communicating properly and you have bad power you prob. won't get debug info).

I can't test it with a wall wart because I don't have a regulated one handy... since the SX tech board has a voltage regulator
built-in, will an unregulated wall wart cause problems?

> Check what it's rated for .. if <= 9v you will prob. be OK. Remember that an unreg. wall wart will deliver much more voltage when NOT under load, i.e., if you check a 9v wall wart with a voltmeter you may see 12-15v as the meter is not (supposed to be) a load per se. Make sure the power plug is center positive. Plug the wall wart in and if power comes on, check the voltage out of the regulator on the board (measure Vdd) and check to see if the regulator is getting hot. The regulator on the Parallax boards is pretty tough -- just pull the power ASAP if *anything* seems amiss. Never hurts to disconnect power from your circuitry and pull the SX to keep 'em safe when you try it out.

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