Customizing both voltage and amperage in a circuit
You will need to shift the voltage level from 1V8 (BeagleBoard-xM) to 3V3 (2.31 Voh). The level shifter will have to put out a minimum of 10uA. Assuming you don't need ultra high speed, this can be done with a 74LVC07/07A with a 1V8 supply and 3V3 10kohm pullups on the outputs.