Extended Configuration Proposal

[soundanalogous]

Copying this over from firmata.org.

Extended Configuration Proposal

for special configuration not covered in pinmode-specific messages

/* set analogReference request
 * 0  START_SYSEX (0xF0)
 * 1  CONFIG_EXT command (0x7C)
 * 2  ANALOG_REF command (0x00)
 * 3  analog reference source (0-4, 0=DEFAULT, 1=INTERNAL, 2=INTERNAL1V1, 3=INTERNAL2V56, 4=EXTERNAL
 *    Values supported are device-specific. 
 *    See http://arduino.cc/en/Reference/AnalogReference and Arduino.h for details)
 */

/* set analogReadResolution request
 * 0  START_SYSEX (0xF0)
 * 1  CONFIG_EXT      command (0x7C)
 * 2  ANALOG_READ_RES command (0x01)
 * 3  analog read resolution (1-32, see http://arduino.cc/en/Reference/AnalogReadResolution for details)
 */

/* set analogWriteResolution request
 * 0  START_SYSEX (0xF0)
 * 1  CONFIG_EXT       command (0x7C)
 * 2  ANALOG_WRITE_RES command (0x02)
 * 3  analog write resolution (1-32, see http://arduino.cc/en/Reference/AnalogWriteResolution for details)
 */

[soundanalogous]

The first of these 3 applies to any board. The 2nd two are Arduino Due-specific for now, but will likely apply to additional boards in the near future.

[ntruchsess]

That was me writing up this proposal. See my pull-request #40. Since the boards support different sets of values I used ifdefs in the code to enable the features that actually work. Not having the board I didn't have a chance to test the DUE stuff though...

[soundanalogous]

I've submitted a new pull request for this. However it's not as straight forward as I initially anticipated due to differences in how AVR and SAM boards handle these methods.

#143

[shahanHasan]

How do i use them with python and pyfirmata to change analog reference to external and pass the reference voltage to analog read ? Any code snippets would be great.