MAX11300 ADC DAC and Teensy

[mortonkopf]

Hi all,

does anyone on the forum have practical experience of using the MAX11300 chip as Control Voltage output?

The MAX11300 chip, particularly the MAX11300PMB1 peripheral module seems to have great scope for marrying to the Teensy to provide stable 1v/oct outputs in a large number, with the board being ready for +-12v regulated source in a Eurorack setting. The GPIO (20 input or outs) are controlled via SPI, and can be set as ADC or DAC (my focus is on DAC), with a set range of -10v to 0v, -5v to +5v, or 0v to +10v. My thinking is that I would like to see if this is something that would lend itself to the Teensy Eurorack environment, with possibly something as simple as using a ref table to read incoming midi values and messaging the MAX chip with a voltage to output.

https://www.maximintegrated.com/en/...rs/analog-to-digital-converters/MAX11300.html

https://datasheets.maximintegrated.com/en/ds/MAX11300PMB1.pdf

its a 12bit DAC, so perhaps not as useful for oscillator side of things.

I haven’t seen much discussion on the forum about this chip, or the breakout module (possibly because it is 20 pounds), other than some mentions in passing.

Just wondering…. before I start heading into it.

an example of using the Teensy MAx11300 combo would be look up tables for Midi note value, and voltages:

eg:
float allVolts[85] ={
-1.000,-0.917 , -0.833 ,-0.750 ,-0.667 ,-0.583 ,-0.500 ,-0.417 ,-0.333 ,-0.250 ,-0.167 ,-0.083 ,
0.000 ,0.083 ,0.167 ,0.250 ,0.333 ,0.417 ,0.500 ,0.583 ,0.667 ,0.750 ,0.833 ,0.917 ,
1.000 ,1.083 ,1.167 ,1.250 ,1.333 ,1.417 ,1.500 ,1.583 ,1.667 ,1.750 ,1.833 ,1.917 ,
2.000 ,2.083 ,2.167 ,2.250 ,2.333 ,2.417 ,2.500 ,2.583 ,2.667 ,2.750 ,2.833 ,2.917 ,
3.000 ,3.083 ,3.167 ,3.250 ,3.333 ,3.417 ,3.500 ,3.583 ,3.667 ,3.750 ,3.833 ,3.917 ,
4.000 ,4.083 ,4.167 ,4.250 ,4.333,4.417 ,4.500,4.583,4.667 ,4.750 ,4.833 ,4.917 ,
5.000 ,5.083 ,5.167 ,5.250 ,5.333 ,5.417 ,5.500 ,5.583 ,5.667 ,5.750 ,5.833 ,5.917 ,
6.000 };

int allNotes[61] ={
24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, //24= c1
36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, //36 = C2
48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59,
60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, //60 = C4
72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83,
84 etc......
};

 

[MarkT]

20 quid for a manufacturers module? That's dirt cheap - professional evaluation boards are usually far more expensive, and this is
basically an evaluation board.

One thing I'd be wary of is the DAC accuracy specs - +/-20 LSB's offset isn't trivial (+/-50mV), and they don't say what the matching
is between outputs for gain or offset, nor if there's anyway to trim it. It seems to be one DAC + sample/hold circuit per pin though,
so hopefully the matching is good, but you'll need to keep the outputs refreshed given the maximum droop rate is 15mV/s.

 

[mortonkopf]

well, probably 30 quid after some postage.... but yes, I take your point, still cheap and very accessible for the DIYer

that droop rate was interesting. sample and hold on Mutable Instruments Kinks is less than 1mV/s as comparison. BUT... refresh rate should deal with that.

 

[recursinging]

The Polyend Poly2 uses the MAX11300 and tracks quite well.

Here's the PCB:

I think you will be able to make good use of this reasonably priced IC. I had plans to make a module with it, but got distracted.

 

[mortonkopf]

@recursinging - very useful, thanks. I saw some discussion on Muff Wiggler and Axoloti forums mentioning the polyend poly, and I see that there is some hope for a stable voltage output and reasonable tracking. those discussions led me to get hold of the dev board and see how it could work with Teensy as an easy DIY for reliable eurorack integration.

https://www.muffwiggler.com/forum/viewtopic.php?t=216139

Shame that you got distracted...

 

[mattkuebrich]

I've been looking into ways to output multiple CVs and the MAX11300 looks amazing. Is there a way to use this chip with the Teensy Audio Library? I assume not, but figured I'd ask.

I found this Eurorack project, which uses the chip with Teensy in a similar way that I'm planning, but not with the Teensy Audio Library.