Agreeing
with ar:
Unfortunately,
I donât think different ranges are possible. From my experience with the
ADC16 board, setting the ranges or other config parameters of the ADC affects
both LTC1859 chips (there are 2 ADC chips, each 8-channel, on-board), because
of the interface with the on-board Lattice CPLD.
Looking
at the ADC16 libraries the code to configure the range:
adc_set_inrng
() {
adc_stop > /dev/null
let BASEIO=`adc_baseio`\|0x2
let BIT6=$1\&0x1
if test $BIT6 -eq 0; then
bit_clr $BASEIO 6 > /dev/null
else
bit_set $BASEIO 6 > /dev/null
fi
let BIT7=$1\&0x2
if test $BIT7 -eq 0; then
bit_clr $BASEIO 7 > /dev/null
else
bit_set $BASEIO 7 > /dev/null
fi
echo `adc_inrng`
}
This
looks like only two bits are configured (the number of bits configured for *one
chip*), meaning that setting the voltage range sets the range for both chips.
In
other words, it is possible to have each chip running at a different voltage
range, but I donât think this is possible with the current logic running on the
CPLD. Might try calling Technologic to see if they know off-hand of any
undocumented config register or have newer code.
All
in all, obviously running everything at +/-5V will allow you to measure
everything you want, just the 0-5V inputs will have half the resolution you
might have liked.
Good
luck,
Stefan
From:
[ On Behalf Of Angel
Sent: Monday, March 01, 2010 8:47 PM
To:
Subject: Re: [ts-7000] TS-ADC16 configuration question
Hi,
I don't think you can.
ar
On Tue, 2010-03-02 at 01:11 +0000, Alex wrote:
>
> I need to sample 4 channels with ADC16 board. 2 channels maximum input
> range is [0 5] Volts, two other channels should have input range [-5
> +5 V]. Does anybody know if I can configure different input ranges on
> different ADC channels?
>
>
>
>