madc

Simple program to read the Overo twl4030-madc values.

The twl4030-madc are 10-bit ADC's with a voltage input range 0 - 2.5v

Download and Build

The Makefile assumes a typical Gumstix OE cross-compile setup on a workstation. You can export a different OETMP in your environment if you aren't using the default Gumstix paths.

~$ git clone git://github.com/scottellis/madc.git
~$ cd madc
~/madc$ make

or for a different OETMP

~/madc$ OETMP=/oe1 make

Copy the resulting madc executable to the Overo however is convenient.

Usage

Assuming you copied the madc program to /home/root on the Overo.

root@overo:~# ./madc -h
Usage: ./madc [options] [channel list]
Options
  -a          Request the device driver average 4 readings
  -m          Machine readable format ch:raw:voltage
  -h          Show this help message

channel list  A space separated list of channel numbers 0-15.
	      If no channel list is supplied, channels 2-6 are read.

  Example: ./madc -a 2 4 6

So for example

root@overo:~# ./madc   
madc[ 2] raw =  413  voltage = 1.01
madc[ 3] raw =  405  voltage = 0.99
madc[ 4] raw =  407  voltage = 0.99
madc[ 5] raw =  405  voltage = 0.99
madc[ 6] raw =  403  voltage = 0.98

Channels 2-6 had 1.0v applied with a bench power supply.

Or two channels, average of 4 reads, output in a machine friendlier format

root@overo:~# ./madc -a -m 2 4   
2:615:1.50
4:618:1.51

Channel 2 and 4 had ~1.5v applied for that test.

The exposed ADC pins on the Overo Summit/Tobi expansion headers.

AGND   : Pin 37

ADCIN2 : Pin 34
ADCIN3 : Pin 38
ADCIN4 : Pin 39
ADCIN5 : Pin 36
ADCIN6 : Pin 35
ADCIN7 : Pin 33  appears to be in use, TODO: research this