WP34s Repurposing Journey PhotoJournal

[MarkHaysHarris777]

I received a copy of the 20b schematic today (thanks, Barry!) via email and discovered that an optional ADM3202AR I|O driver chip is available which would provide very nice optional buffering and ESD protection for the Tx Rx pins on the micro-controller (worth looking into). The chip would have to be surface mounted, and the J5 J6 zero-ohm jumpers would need to be removed. Might be fun.

I'm wondering if Marcus controls the RS232ON input to the Q2 BC856A transistor?

Anyway, I also noticed that TestPoint (TP11) is connected directly to the power switch; which means that if a usb-like connector brought the J3x pins out-bound along with the TP11 pin, the flashing|updating could be handled completely under automation, because the automated controller would be able to turn the calc on with a ground shot (ground TP11), similar to turning it 'off' by giving a ground shot to J32.

So, FlashBox v2.0 is in design consideration and will have all of the instrumentation of FB1 (including mA meter and voltage latches) but will also be entirely self contained (on-board battery) and fully integrated and automated. The flashing|updating will be under control of a Raspberry PI (from inside the FlashBox) and the flash image will be selectable by plugging in a custom thumb drive.

Coming sonn, stay tuned. FlashBox v2.0 will be portable, self-contained, and fully automated--- plug in the hardware (20b - 30b) and press GO...

Cheers,
marcus