Voltage Testing of XO-1.75
This procedure is for verifying firmware startup at different core voltages.
It assumes that the board is hardware-configured to start at a core voltage of 1.4V.
Test booting at 1.4V by powering on the board in the normal way.
To test booting at 1.345V :
- Attach a serial port to the XO-1.75.
- Get into CForth by holding down the rotate key and powering on.
ok b gpio-set ok ofw
It should boot normally.
To test booting at 1.4V (as modern CForth sets this GPIO to 1 -- 1.345V -- immediately upon boot):
ok b gpio-clr ok ofw