SparkFun Electronics Commentsurn:uuid:214d0e4e-f1b1-d287-ce26-ac5b4c9f82492024-03-29T09:51:12-06:00SparkFun ElectronicsCustomer #1484327 on Enginursday TapasCustomer #1484327urn:uuid:66d41ac8-462b-fdb9-abdc-5334dc539a5f2018-12-11T03:28:53-07:00<p>Hi,
I am running into audio problems doing the 2 audio shield w. teensy 3.2 setup.
I am using the standard test code example, included at the end of this post.
I have removed the pin 15 capacitors on each shield
I have done all the mods to the second shield described in the sparkfun tutorial (linked from the quad page):
I get the message playing file 1 & playing file 2.
The 1/2 channel card works fine. Nothing at all on the 3/4 channel card. There appears to be no data on pin 15. If I temporarily short the pin 22 pad to the pin 15 pad, I get channels 1/2 playing on the 3/4 shield, as you would expect. I built two different boards - each with the same problem. I also tried a modified board I had successfully used in the past - this also didn't work.
I also tried setting pin 15 to output mode (not in the example).
I've tried running at 96 Mhz and also 72 Mhz.
Has something changed re. the support for the Teensy 3.2?
I have tried several codes...
I should also specify that we did the mods necessary to stack the two audio shields and that we do not have any shorts on the solders that I made ^^
Thanks to anyone who has some ideas!</p>
Customer #1161185 on Enginursday TapasCustomer #1161185urn:uuid:ecb5b0ef-0108-ca36-0aab-5b6daa1b15c12017-10-06T12:03:03-06:00<p>Asked on the PJRC-forum, quickly got a response;
https://forum.pjrc.com/threads/46781-Dual-Audio-Adaptor-Boards-with-23LC1024-RAM-chips<p>Short answer: Yes, it is a problem. It should be solvable though by cutting the connection to pin 6 on one of the boards, preferably such that the pull-up resistor is still connected to the CS pin on the memory chip, and then rewire it to be connected to a different pin on the teensy.</p></p>
Customer #1161185 on Enginursday TapasCustomer #1161185urn:uuid:28fd4941-1bbb-b9ae-09a5-322527d027c92017-10-03T15:14:04-06:00<p>So, I followed the guide and slightly adapted it to fit the Teensy 3.6, and it all seems to work.<p>Since I need some heavy delays, I soldered on a RAM on each audio board (my first on something that small, not easy), although in retrospect one chip might be enough. I haven't tried it yet, but just inspected the schematics, and now I can't figure out whether it would work, or (in worst case) fry the RAM chips, since they are on the same CS (pin 6).</p><p>Is this a problem? Any way to avoid it? (preferably without the need to unsolder the RAM chips).</p></p>
Customer #258806 on Enginursday TapasCustomer #258806urn:uuid:29b56409-58a8-6cc5-ac85-b13e6d2957222017-09-09T02:47:56-06:00<p>Several months after this tutorial was written, Teensy 3.6 was released. It run at about double the speed of Teensy 3.2 and have 4 times as much RAM. That extra capacity can be pretty useful for audio synthesis, especially if using 4 channels.<p>This mod works the same way, except the extra RX signal goes to pin 38 on Teensy 3.6, rather than pin 30 as documented for Teensy 3.2. This is documented in the Audio Library Design Tool right-side panel for the I2S Quad object.</p><p>https://www.pjrc.com/teensy/gui/?info=AudioInputI2SQuad</p></p>
Customer #258806 on Enginursday TapasCustomer #258806urn:uuid:089c86fb-d01b-440b-db83-a00a182fcf6f2017-09-09T02:18:31-06:00<p>Confirmed, the arrow is correct. The TEXT IS INCORRECT. It should read "trace between the center and <strong>right</strong> pads of the I2C address selector also need to be cut".<p>While not easy to see in this low-res web image, when you look at the actual PCB with a magnifier to actually make this mod, you will see the trace is between the center and right side pad.</p><p>The 0.1uF capacitors on pin 15 will cause trouble for the extra data signal. If you connect audio shields together in the simplest, most straightforward way where all pins connect (similar the photos), both of their pin 15 pads connect together. Both capacitors need to be removed, since either would cause trouble.</p><p>If you were to cut the header, so there was no connection to pin 15 on the unmodified board, so that neither Teensy nor the modified board connects to it, then leaving the capacitor in place on the unmodified board would be fine. It can't interfere with the 2nd data signal if it's not connected between the boards. Obviously the capacitor must be removed from the modified board, so no matter how you connect between the 3 boards, you will need to do the capacitor removal on at least the audio shield where you cut the trace, soldered the alternate I2C address pads, and arranged for the data signals to do to other pins.</p><p>With an ordinary soldering iron, probably the simplest way would involve building up a small bead of solder on the tip of your iron. The part is so small that you can just lay a bead of solder on top to melt both sides at the same time. The part might stick to your iron's tip as you pull it away. If not, just a gentle press will easily push it aside from the pads, towards the large open area near the edge of the board. You can then pick it off with tweezers, if it doesn't fall off from the slightest touch.</p></p>
Customer #863010 on Enginursday TapasCustomer #863010urn:uuid:5105c569-6735-2342-4106-725e82b97c892016-11-12T20:30:15-07:00<p>I know this is an older post, but hopefully someone sees my comment. I'm rather new at all this, so I need some assistance. The directions say to cut the trace between the left and center I2C pads, but the picture is pointing to the space between the right and center. Could someone please clarify that for me? Do I cut the left one, then basically reconnect the two pads with the solder blob? If so, why not just leave the trace connected to begin with?<p>Also, what's the best way to remove the capacitor in the first step? And do I remove it on both boards?</p><p>Thanks!</p></p>
nightliz on Enginursday Tapasnightlizurn:uuid:3f3c2e4e-84b0-b542-7400-bcd1e1e1a68f2016-03-17T13:00:15-06:00<p>"Floobydust" is my new favorite word.</p>
scharkalvin on Enginursday Tapasscharkalvinurn:uuid:274aeef4-2649-db18-e14c-19664532c4932016-03-17T10:30:27-06:00<p>A better way to stack the Teensy audio boards might be to make use of those long pin Arduion stackable connectors on the top board so you can just stack the two of them together, and then put the Teensy on top. In fact, that's how it's done on the Teensy web site.</p>
Customer #286247 on Enginursday TapasCustomer #286247urn:uuid:b8f1a29f-38d1-dd08-4c43-c58d08c9b6b12016-03-17T10:04:21-06:00<p>Thanks for the "Heads Up" on Bob Pease! I really liked his articles and I grabbed the E-Book.</p>