XADC

Peter Meerwald pmeerw at pmeerw.net
Tue Jun 3 23:47:21 PDT 2014


Hello,

> I recently found that you developed a driver for XADC and I thought I
> enable it (see patch below). But it seems something is not working
> correctly. The values I tested don't seem to be right and also fixed.
> I.e. they don't change over time or across boards:
> 
>   # cat in_temp0_scale 
>   123.040771484
>   # cat in_voltage0_vccint_scale 
>   0.732421875
>   # cat in_voltage0_vccint_raw 
>   1384
>   # cat in_voltage1_vccaux_s[ 1203.660637] random: nonblocking pool is initialized
>   # cat in_voltage1_vccaux_scale 
>   0.732421875
>   # cat in_voltage3_vccpint_scale 
>   0.732421875

the _scale values are supposed to be constant; their purpose is to scale a 
measurement so that the result is in a given unit

e.g. in_temp0_scale scales in_temp0_raw so that the result 
(in_temp0_raw * in_temp0_scale) in milli Celsius

in_voltage0_vccint_raw * in_voltage0_vccint_scale is supposed to give 
milli Volts

so in_voltage0_vccint_raw should vary accross time / boards (and voltage 
hopefully :), but not the _scales

regards, p.

-- 

Peter Meerwald
+43-664-2444418 (mobile)



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