Using ADC on FX30

#1

Hi I was looking through the datasheet for the fx30 and it says that its 0-5V and 0-10V but in another forum post someone said that you cannot select these voltages and the user guide is wrong? Is this correct and what is the actual voltage the ADC runs on is it 1.8V like the WP modules? Sorry would like to know because 1.8V is difficult to interface with sensors.

#2

Hi sast5,

You can control the ADC select line using the following procedure:

cd /sys/class/gpio/

echo 29 > export

cd gpio29

echo out > direction

Then depending on the range you want, drive either high or low:

echo 1 > value

echo 0 > value

Note: This method is not persistent over a reboot.

Alternately, you can configure it using the AT command: AT+WIOCFG=29,…
Please see the AT command reference guide for WP85 module for details on the command.

Originally we intended to add an FX30 specific AT command to control the signal, but this hasn’t be implemented, hence the comment regarding the voltages cannot be selected. We usually recommend not using the AT+WIOCFG command because if one isn’t careful, it could cause issues with the device.

Sorry for the confusion.

BR,
Chris

#3

Okay thanks that solves my issue but does direction mean from max 5V to max 10V or something else. By not persistent I can just run a an app to do this every boot correct?

#4

Direction means the GPIO is configured as an output.

Set the range from 0-10V:
echo 1 > value

Set the range from 0-5V (or leave as default):
echo 0 > value

This method is not persistent over a reboot, however the AT command is. Or yes, you can create an app or script to set this up every time upon startup.

BR,
Chris

#5

Okay sweet thank you very much