TS-7120 CPU ADC
The TS-7120 has two channels of ADC, and those inputs are available on the CN16-A connector, as 6UL_ADC_0 and 6UL_ADC_1.
The standard linux kernel offers a simple interface to the ADC that does not require any sort of programming to use. For example, to see the "raw" reading from the AN_IN_1 input, type the following command:
WORK IN PROGRESS
cat /sys/bus/iio/devices/iio\:device0/in_voltage4_raw
To convert this raw value to a voltage, it must be multiplied by the "scaling factor", which can be found by typing the following command:
cat /sys/bus/iio/devices/iio\:device0/in_voltage_scale
The result will be in millivolts. If you have the bc utility installed, you can enter the following command:
echo `cat /sys/bus/iio/devices/iio\:device0/in_voltage4_raw` \* `cat /sys/bus/iio/devices/iio\:device0/in_voltage_scale` | bc
To switch to the 10.9V input range, the appropriate enable must be set high. Each input AN_IN_1 through AN_IN_4 has its own enable, EN_ADC1_10V through EN_ADC4_10V, and these are controlled by GPIO #10 through #13. For example, to switch AN_IN_1 to the 10.9V range, run the following command:
tshwctl -a 10 -w 3
Note that the result must now be multiplied by (10.9/2.5). Note also that the input impedance will now be around 2k ohms.
To switch to the 20mA current-loop mode, the appropriate enable must be set high. These are EN_CL_1 through EN_CL_4, and are controlled by GPIO #6 through #9. First select the 2.5V range as follows:
tshwctl -a 10 -w 1
And then set the EN_CL_1 enable high as follows:
tshwctl -a 6 -w 3
| # | 'raw' | 2.5/10.9V Select | 20mA Loop Select |
|---|---|---|---|
| AN_IN_1 | in_voltage4_raw | GPIO 10 | GPIO 6 |
| AN_IN_2 | in_voltage5_raw | GPIO 11 | GPIO 7 |
| AN_IN_3 | in_voltage8_raw | GPIO 12 | GPIO 8 |
| AN_IN_4 | in_voltage9_raw | GPIO 13 | GPIO 9 |
| Note: | The four ADC inputs use the CPU ADC inputs 4,5,8, and 9, corresponding with the 'raw' entries in the above table. |