Calibration using 100Ohm

[JochiSt]

I tested the OFM using two 100 Ohm resistors and a DAC sweep. (From the calibration, it is known, that 32 LSB DAC are about 1mA measurement current)

Channel 0

Channel 1

Overall it seems, that there is a bit to much noise for the low voltages (and currents). This needs further investigations, whether there is some room for improvements.

[JochiSt]

Added 100nF at the position of D5 and D6.

[JochiSt]

Since this effects only channel 0, the results DAC sweep looks more smooth.

And the precision has also increased. Maybe further capacitors are needed to stabilise the measurement circuit.