Output suddenly only 0.6v

[Furlong]

Hi everyone- first posting on this site, but fingers crossed.

Recently bought a rev-it 28X1 board to revise my knowledge on Picaxe, having dabbled in a few years back when teaching. Working through basic programs, all going well- LEDs flashing, etc. Try to use analogue input. Didn't work- no output. Switch back to flashing LED code- now only have 0.6v out! Not enough to drive LED or anything else. Have tried a different project board and Pic- same result. I know there's probably a 'senior moment' behind this, but must swallow pride and ask the world out there. Thanks in advance. PF

 

[tiscando]

Check your battery or your power supply. The battery may have suddenly gone flat, or your power supply got turned off/down. Check by measuring the picaxe's supply voltage, and that the download circuit is correct.

 

[hippy]

Did you accidentally connect the analogue in to that pin ? That or some other short on the output could have blown the output circuit for the pin.

It could also be that having reverted your code that it's not doing what it should do. Double check the code and pin being used, and you can also try some test code to toggle all pins in sequence or together.

Fingers crossed that it has just been a D'Oh! moment not anything worse.

 

[Technical]

It probably is working fine - we guess you are sticking your voltmeter across the buffered open-collector output and 0V, which will read 0.6V with nothing connected!


Outputs go between V+ and the open-collector output, not between output and 0V.

 

[Furlong]

Thanks all. Technical was the winner! The book circuits I'm using refer to straight output, but the board goes out through Darlingtons and are pulled up (correct term?). Weird thing is I'm convinced I was doing it the other way before and it worked. Anyway, must press on before I forget it all again. PF