Hi all,
I am trying to mount a light SCA demo using Chipwhisperer Lite as a portable oscilloscope and ArduinoMega2560 board as target.
Since I/O output I use for triggering is 5V I have to convert it to 3.3V logic to be fed to the CWLite. As recommended, I am trying to use CW506-02 for this but I only manage to obtain something like 2.3~2.4V.
From the Arduino I connect to JP2 the trigger output to PIN IO4 and the IOREF (which is a constant 5V output) to PIN VREF so that the CW506 knows that the signal on IO4 is 5V logic (if I understood correctly it can be used as VCCIO which is the voltage on the right part of the CW506).
For using VREF as VCCIO I put both SW1 and SW2 to the right while keeping SW3 on the left (again if I am right this last one does not matter since it only provides 3.3V on JP2).
Eventually, I put all switches but the TIO4 to off on SW4 because I am only interested in the TIO4.
May be an additional point is that my Arduino board is connected to a laptop with USB so has its own source of power.
With the docs and my little understanding of electronics, I assumed this was the correct configuration. However, probing on JP3 the TIO4 signal I obtain a 2.3~2.4V signal. Interestingly (or not) this is somehow like the voltage shrinking was “performed” twice since 5 0.66 = 3.3 and 5 0.66 * 0.66 = 2.4. I checked the TP11 which shows a 5V signal what is what I expected (if understanding correctly the doc it means that the board will actually convert from/to this 5V to/from 3.3V). Also I checked that on JP4 I still have a TIO4 at 5V.
Since I do not understand well schematics (math background) this clue is of little help but may be one of you may see what is going wrong here. May be I have to connect more PINS to the 20-PIN slot (but do not see why I should) ?
Thank you for your help,
Best