how do I read values of LRADC0/1?

Started by dsp, March 19, 2015, 03:10:16 PM

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dsp

Hello,
I would like to read the analog voltage of a sensor and use it in puredata or python.

1) how do I read the values of LRADC? I only find information how to read the digital I/Os.
2) Is this a sensible way to connect an analog sensor to the LIME2? or would it be better to use e.g. a Pinguino Board and connect this to some GPIO with I2C?

I am using the A20 LIME2 board to make an electronic music instrument and this is my first post here.
Any help appreciated...
Dominik

dave-at-axon

What resolution do you need from your sensor? What is the range of output from your sensor?

The LRADC is only 6 bit so not very good for general sensor interfacing as this is only 64 bits.

Better you use an external ADC with higher bit count with a min of 12 but ideally 16 bit gives the best resolution. There are a number of I2C interfaced IC's that can be used with ease with the A20. I use the MCP3428 4 channel 16 bit device and it gives a nice clean signal.

deskwizard

Just to shime in, I am with Dave on this, an external I2C ADC would probably be the best course of action

Gerrit


dsp

thank you for your answeres!

I have used one Arduino board now and connected it via I2C. This basically works.
I need to learn a bit more about I2C though: I can only send/receive one byte number.
I would like to send 10 bit value. but it's better than 6bit :)

thank you Gerrit. Good to know which road to turn to get the LRADC to run. The name sounds to me like it could be used as audio in...