Quad channel output on Teensy 3.6

If you're just adding signals with sketch-controlled gain levels, there's probably little to be improved beyond simply using lots of 4 channel mixers. Well, other than the aesthetics of your source code and the fun & challenge of digging into the internals of the library.

And the removal of 140 audio connections & the lower complexity of the diagram leading to less bugs. Would you write messy C code?

Paul; please don't disincentivise wanting to make a contribution, this is just the start of a few planned audio objects.
 
Hi, please excuse my late answer.
The board is working so far, and it's really great.
I had'nt much time for intensive testing so far, sometimes plans are "upated" by other circumstances.., but I have more time now :)
 
Hi,
I wired up myself a TDM board for some awesome multiport fun, but cannot seem to compile the code....I keep getting an errors that include the follwing statement "'AudioInputTDM' does not name a type"....It is probably some dumb mistake. Other than adding some libraries I plan to use in the future the code is pretty much auto-generated from the online GUI Audio System Design Tool. Any help would be much appreciated!

Thanks,

Here is my code:

#include <Wire.h>
#include <TEA5767Radio.h>
#include <Audio.h>
#include <Wire.h>
#include <SPI.h>
#include <SD.h>
#include <SerialFlash.h>
#include <control_cs42448.h>

// GUItool: begin automatically generated code
AudioInputTDM tdm1; //xy=145,160
AudioOutputTDM tdm2; //xy=398,160
AudioConnection patchCord1(tdm1, 0, tdm2, 0);
AudioConnection patchCord2(tdm1, 1, tdm2, 1);
AudioConnection patchCord3(tdm1, 2, tdm2, 2);
AudioConnection patchCord4(tdm1, 3, tdm2, 3);
AudioConnection patchCord5(tdm1, 4, tdm2, 4);
AudioConnection patchCord6(tdm1, 5, tdm2, 5);

AudioControlCS42448 cs42448_1; //xy=148,381
// GUItool: end automatically generated code

void setup() {
// put your setup code here, to run once:
}
void loop() {
// put your main code here, to run repeatedly:
}
 
Can someone who has tried the TDM board comment on the sound...After soldering up two different TDM boards they both sound pretty horrible. I have a feeling it is due to my sub-par soldering skills, but was just curious if someone could confirm that it is a "me" problem. I am using teensy 3.6, not sure if that makes any difference.
 
Gerbers, yes. Eagle, no, I don't use Eagle, so no Eagle format files.

Are you wanting to get this board made from some place other than OSH Park?
 
Actually I just wanted to compare your board to the one that I designed. I already ordered some of your boards from OSH Park, but I'm thinking about doing another with the active outputs. Any design reference would really help. By the way, this is fantastic work, and I really appreciate you putting it out there.
 
Any design reference would really help.

I just copied the passive single ended circuits right from the CS42448 datasheet. I added a CAT811T reset chip, and connected the digital signs to Teensy, and added some decoupling capacitors. Everything else is the exact circuits from the CS42448 datasheet, just replicated 8 times for the outputs and 6 times for the inputs.

I never made *any* schematic at all. I just put the parts into the layout and connected them.

Except for complex analog circuits, I almost never draw a schematic. For me personally, it seems like a waste of time. I know this sounds crazy to many people, but consider the schematics so many people "draw" these days, especially in the maker / open hardware world. They're usually just the parts scattered around a sheet with net names attached to all the pins. What's the point in that, other than going through the motions to satisfy some "work flow"? Especially for quick prototypes like this CS42448 test board, I personally can make the whole thing very quickly by just wiring up the stuff right in the layout. That gives me more time for coding, documentation, answering questions and actually helping people with their projects.

Yes, the it sounds very good. I havn't had any problems.

Erin (aka "Soldering Goddess") does excellent work. :)
 
Hi Paul,

Thanks for the reply. Would you mind sharing the gerbers? I don't usually start with schematics either, but just seeing the board connections would be a huge help. I should have your boards from OSH Park in a few days, but in the meantime, I'd like to compare your layout to mine if that's possible.

Thanks again,
Colin
 
Would you mind sharing the gerbers?

Ok, here you go.

Of course this is only a 2 layer board where you can see all the connections on OSH Park's previews, but maybe a dedicated gerber viewer is easier?
 

Attachments

  • cs42448_test.zip
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Hi Paul,

Thanks again for the gerbers - they've been a huge help so far. The one thing I can't figure out is how you're getting power to analog voltage. Pins 53 and 44 (VA) seem to be connected to GND via the 10nF caps, but I don't see how they're getting 3.3V. Can you clarify?

Thanks!
Colin

VA_PWR.jpg
 
Can someone who has tried the TDM board comment on the sound...After soldering up two different TDM boards they both sound pretty horrible. I have a feeling it is due to my sub-par soldering skills, but was just curious if someone could confirm that it is a "me" problem. I am using teensy 3.6, not sure if that makes any difference.

I just made a 2nd batch of 3 boards. This time I broke down and made them with solder paste & a stencil. All 3 look great, but for some reason the audio still sounds like it is being passed through a kazoo. In other words, there is some noise and it has a hum. The hum is not constant but instead associated with the audio. Is it possible I am frying the codec chip? I was maybe a little careless with the reflow temperature, I just used a frying pan on my stove. But I took it off right after the past started flowing. Looking at the chip datasheet shows nothing about reflow temperature but absolute maximum storage temperature is 150C and I also noticed in the revision history that a change was made to the temperature values, but I could not find the old values for the temperature. I would find it surprising if the reflow is below 260C, but maybe this temperature revision is a sign that these chips are pretty sensitive to higher temperatures. Anyway if anyone has an idea of what I might be doing wrong I would appreciate it.

Thanks,
Mike
 
Pins 53 and 44 (VA) seem to be connected to GND via the 10nF caps, but I don't see how they're getting 3.3V. Can you clarify?

VA is powered by 5V from Teensy's VIN pin through a ferrite bead (just to the right of Teensy's VIN pin).

VA is *not* connected to 3.3V at all. 5 volts is used for the analog power.

There looks like a via right below the top 10nF capacitor. Does that connect to power?

The via just below the 10nF capacitor and just above pin 43 connects to a vertical trace on the bottom side which runs all the way up to the top of the board, where another via connects it to a horizontal trace over to the ferrite bead and a 10 uF capacitor, which low-pass filter the 5V power to provide a (hopefully) clean 5V power for VA.

Here's a screenshot with the VA net selected (white). You can also see all the pads connected to GND are in a dull green color and the pads connected to 3.3V are a dull light blue color.

sc.png
(click for full size)
 
Hi Paul,

Just wanted to say that I just finished building and testing your board and it sounds great! Thanks for all the effort you have put into this endeavor.
Cheers,
Colin
 
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