Voltage Testing of XO-1.75

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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