OctoPROBER REV 0 board works!*

20140205_201657

*With hardware fixes

I was having an issue with the FT230X being active while the 3.3V rails being turned off. The FT230X would backfeed voltage down the TXRX lines into the propeller which would power the 3.3V rail to ~2.7V causing the soft power switch circuit to turn on. I fixed this by running the RESET pin of the FT230X to the propeller and pulling it up to the switched 3.3V rail. The propeller can control whether the FT230X is in suspend mode or is active. Pulling RESET low will HI-Z the TXRX pins and allowing the propeller to turn off the soft power circuit completely without voltage backfeed.

Changed the 16×2 char display from running in 4-bit parallel mode to serial com. This saves 2 I/O lines and is much faster then the 4-bit mode.

Since the main way of charging the OctoPROBER is over USB I needed a way to disable the auto reset. Don’t want the device to reset when its taking samples and low battery warning pops up! This is cause when a computer connects to the FT230X it sends a reset signal to the FT230X which is connected to the reset line on the propeller. Disconnected that and routed the FT230X signal to a free I/O line. This way the prop can control whether or not to reset upon connecting to a computer.

Couple more hardware systems to test then REV 1 boards will be ordered!

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