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#49263 by fzabkar
Thu May 22, 2008 12:10 am
I notice that some motherboards encode the CPU core voltage jumpers in simple binary format. I suspect that in these cases the motherboard's power supply uses a D/A converter. Such a design makes it easy to fill in the undocumented voltage settings.

The following example lists all the possible core voltages for a PC-Chips M577 motherboard. The table should be viewed with a fixed width font.

Core Jumper JP6
Voltage D C B A

MSB LSB
2.0 0 0 0 0
2.1 0 0 0 1
2.2 0 0 1 0
2.3 0 0 1 1
2.4 ------ 0 1 0 0 (0100 = binary 4, for AMD K6-III)
2.5 0 1 0 1
2.6 0 1 1 0
2.7 0 1 1 1
2.8 1 0 0 0
2.9 1 0 0 1
3.0 1 0 1 0
3.1 1 0 1 1
3.2 1 1 0 0
3.3 1 1 0 1
3.4 1 1 1 0
3.5 1 1 1 1

1 = jumper installed
0 = jumper not installed