---+ Firmware Quirks
This will change when the ADC device registers are automatically assigned...
The firmware contains an ADC offset register in order to compensate for the 1.25v offset at its input. This register currently defaults to 0.
The correct offset should be a negative value; we currently use the positive representation of the corresponding 2's-complement value. Run the following commands (as root) on the board:
Fixme. PGA should be 2; input buffering should be ON.
This topic: CryoElectronics > WebHome > FirmwareQuirks Topic revision: r2 - 2009-08-26 - WinterlandUser
ADC offset not set by default
This will change when the ADC device registers are automatically assigned...
The firmware contains an ADC offset register in order to compensate for the 1.25v offset at its input. This register currently defaults to 0.
The correct offset should be a negative value; we currently use the positive representation of the corresponding 2's-complement value. Run the following commands (as root) on the board:
This value is 14680064=2^24-(1.25v / 5v) * 2^23.# cd /sys/bus/of_platform/devices/84020000.cryo-sequencer/seq/ # echo 14680064 > adc_offset
ADC Device Registers not configured by default
The ADC has several gain registers that should be programmed consistently to maximize performance. These registers should be programmed as follows: Fixme. PGA should be 2; input buffering should be ON.
This topic: CryoElectronics > WebHome > FirmwareQuirks Topic revision: r2 - 2009-08-26 - WinterlandUser
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