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[wp34s] Permanently damaged machines when flashing
07-25-2015, 06:47 AM (This post was last modified: 07-25-2015 07:05 PM by Perre52.)
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RE: [wp34s] Permanently damaged machines when flashing
The maximum supply voltage Vd of the Atmel processor is 3.6V.
However the input data pins can have a Vd + 0.3 V. That's 3.9V without any damage to the processor.
I flashed mine yesterday with a BV101-4 USB to serial interface cable.
The max voltage on the Tx pin of this interface is 3.85V.

I did fry a calculator but not by programming the calculator. I used a power supply as a voltage source for my calculator during programming. And the voltage on this supply was 9.0V ! I noticed the fault but it was to late.

Try measuring the current when the calculator is on. It should be around 5 mA.
If you measure this value chances are great that your calculator isn't dead but just "sleeping."
This is also the reason that I use a power supply instead of the batteries. I can measure the current and know if my calculator is on (5mA) or off (0mA) during programming.

The HP programming cable uses a ADM3202 IC from Analog Devices.
This device draws its current from the calculator batteries.
You can find more about this cable here:
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RE: [wp34s] Permanently damaged machines when flashing - Perre52 - 07-25-2015 06:47 AM

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