Sunday, February 17, 2008
USB up and running
I took a shot at trying to run my prototype board this evening. I had counted pins wrong and had the power and ground lines running to the wrong pins. That caused my 7805 regulator to overheat, but didn't appear to hurt anything else. After I fixed that...
Bingo, it worked! Windows did its little noise that it makes when it notices that a new USB device has been detected and the whole tootie.
I'm designed my prototype board somewhat differently than Vladimir's and didn't include his pot adjusting voltage to a A/D pin. The software that Vladimir sent along for the PC side comms, however, recognises the board perfectly.
The 10 foot cable I used works properly, so Tommelise 2.0 doesn't have to be particularly close to my PC. I can say goodbye to serial comms and Max232 chips. Life gets a lot nicer with high speed comms. A LOT of the stuff that I was trying to do in the firmware is going to happen in the PC now where I can put Visual Studio to work on it rather than figuring out screwy little ways to make things happen in firmware.
One really, really cool feature of both USB and the prototype board is that if you don't have power on the prototype board the USB provides the 5 v power to run the 18F4550 chip and the darned thing runs properly anyhow.
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