CPU ADC input for encoder conversion table

I'm using Pmac2A/PC104 with OPT12. 12bits ADC input, I wish to use this input as the motor feedback device.

I did follow the instruction set the following

CPU Analog Inputs

I903 = 1746 ;Set ADC clock frequency at 4.9152 MHz

WX:$C014, $1FFFFF ;Clock strobe set for bipolar inputs

M105->X:$0710,12,12,S ;ADCIN_1 on JMACH1 connector pin 45

M205->X:$0711,12,12,S ;ADCIN_2 on JMACH1 connector pin 46

During set-up encoder conversion table, there are only "Acc28 A/D register (no rollover)" in conversion type. Source Address "$C005 PMAC2(ADC1A)"

But, I found that the value at position not tally to the value M105. The origin position feedback is 16 bits data, how to configure it to 12 bits?

yfleong,

You have to use the conversion method of "Parallel Y-word data, no filtering" ($2) for this application. Here is an example:

WY:$720,$200710,$00C00C

WY:$722,$200711,$00C00C

Sina,

follow your instruction, I103 = $710. Currently, I found count different by 128 compare to M105.

Previously use A/D conversion of location $C005, different by 16 count.

Any idea?

yfleong,

You have to set:

I103=$721

I104=$721

I203=$723

I204=$723

If you want to use the ADC as your feedback.

Sina,

I did set this before, not working. Totally no response form address $721 even I change the bit enable mask value to $000FFF.

regards

yfleong,

I strongly suggest for you to give a call to tech support hotline (818)717-5656 so someone can take a look at your setup.