Analog Out - Original & Pico??

[espruino-discuss2]

Posted at 2015-04-02 by LawrenceGrif

I've just been looking at the Pico pinouts and see there is NO DAC?
Also the Classic mentions a DAC but I can't see a pin to be used?

So I'm I right in saying I can use either board for Analog out?

[gfwilliams]

Posted at 2015-04-02 by @gfwilliams

There's no DAC on the pico - the F4 chips just don't have them. The original board has 2 on the middle row of pins though.

However even without the DAC you can do PWM output on most pins with as analogWrite. With a cap and resistor you can still get a pretty good output

[espruino-discuss2]

Posted at 2015-04-02 by LawrenceGrif

Gordon thanks, Arrrr I need accuracy & linearity
OK I've just seen DAC's on Classic are you still continuing to make them?

[gfwilliams]

Posted at 2015-04-02 by @gfwilliams

Yes, absolutely - I'll be selling both for the foreseeable future.

If you absolutely need a DAC on the Pico, there are always external DACs too.

[espruino-discuss2]

Posted at 2015-04-02 by LawrenceGrif

Thanks good to know I'm doing POC wireless cable replacement of a 4-20mA sensor.
I've sourced some precision 3.3v to 4-20mA amps so will use the Original for receiver and PICO for transmitters.

I've seen both Sparkfun & LadyA both do a 12C DAC brake out so when I get time I will have a play.

Happy Easter to all on the Forum.

[espruino-discuss2]

Posted at 2015-05-07 by LawrenceGrif

What should I expect as output voltage when writing 1.0 on the Original board?
I'm only getting 3.14 and the 3.3v supply is only 3.2v.

Same as I'm going to have to put an wee amp to get to 3,3v.

[espruino-discuss2]

Posted at 2015-05-07 by DrAzzy

See page 106 for ST's specs:
http://www.st.com/web/en/resource/technical/document/datasheet/CD00191185.pdf

[espruino-discuss2]

Posted at 2015-05-08 by LawrenceGrif

@drazzy thanks for this.