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  • jkoffman's Avatar
    09-08-2020, 12:17 AM
    Ok, I'm a bit stymied here. Based on the official combinations in output_i2s_quad.cpp (7 and 32, 32 and 9, or 9 and 6) it would appear the the two output channels need to be consecutive. This may be why a value of...
    3 replies | 196 view(s)
  • jkoffman's Avatar
    09-07-2020, 09:49 PM
    Well, I finally had enough time to play with this! I started out by testing both hex and quad output with a simple sine wave object feeding them. That all worked well. Then I started hacking away... Sadly...it...
    3 replies | 196 view(s)
  • jkoffman's Avatar
    09-06-2020, 07:52 PM
    Ah, thank you very much Paul! So based on this I'm seeing 4ma? Am I reading that right? Thank you!
    3 replies | 210 view(s)
  • jkoffman's Avatar
    09-02-2020, 09:04 PM
    I'm running out of pins... Yes I could go to the Teensy 4.1, or I could use the backside pins on the T4.0, but I'd like to try solving this another way. So, some questions... On the ST7735 examples for the Teensy...
    13 replies | 242 view(s)
  • jkoffman's Avatar
    09-02-2020, 08:22 PM
    Hi all, I can't seem to find a reliable answer for the current capability (source/sink) of the I/O pins on the Teensy 4.0. I thought that info would be in here: ...
    3 replies | 210 view(s)
  • jkoffman's Avatar
    09-01-2020, 02:11 AM
    Semi-related question - Kurt, am I able to use a different pin for D/C (other than pin 9)? I might need that for I2S audio... Thank you!
    13 replies | 242 view(s)
  • jkoffman's Avatar
    09-01-2020, 01:54 AM
    Just an update. I left one of the working displays for a couple days, and when I powered up my test setup today, it didn't work. I swapped to my other working display and...nothing again. I'm reasonably sure this might...
    13 replies | 242 view(s)
  • jkoffman's Avatar
    09-01-2020, 01:46 AM
    Hi all, I'd love a double check on this. I've been spending a bit of time learning about I2S on the Teensy 4.0. I understand that there are a maximum of 5 pins can can do I2S. I'm looking at going for quad in/quad...
    3 replies | 196 view(s)
  • jkoffman's Avatar
    08-30-2020, 02:05 AM
    I'm starting to switch to VSCode with PlatformIO. Still early in the transition as I'm working on a few things and haven't had time to properly dive in. Agreed on the usefulness of the plotter. Seems like an...
    25 replies | 767 view(s)
  • jkoffman's Avatar
    08-29-2020, 08:06 PM
    Great thought! I gave it a try but no dice. I couldn't get the actual LCD off the board, so I started closely inspecting the module. There appear to be 5 diodes (D1-5, you can see them in this photo:...
    13 replies | 242 view(s)
  • jkoffman's Avatar
    08-29-2020, 04:22 PM
    Here's the latest! It looks like of the 5 modules I have, only 2 are working. When I started I must have grabbed a bad one, then when I grabbed another to double check, it was also bad. Luckily the 3rd I grabbed was...
    13 replies | 242 view(s)
  • jkoffman's Avatar
    08-29-2020, 03:38 PM
    Hi Kurt, Yep, I moved to a Teensy 3.2 as I knew I had that exact setup working with an ST7735. So interestingly, I grabbed another LCD randomly from the pile, and this one worked. I'm working to characterize...
    13 replies | 242 view(s)
  • jkoffman's Avatar
    08-29-2020, 03:16 PM
    Still plugging away at this. Haven't had time to solder up shorter wires, but I will hopefully do that soon. I did jump back a few steps to double check myself. I went back to a Teensy 3.2, and ran it with an existing...
    13 replies | 242 view(s)
  • jkoffman's Avatar
    08-28-2020, 12:42 AM
    Thanks for trying it out, I appreciate it. I gave your version a try but still no love here. The only modification I made was to the reset pin definition. I'm going to rewire everything tomorrow in the hopes that my...
    13 replies | 242 view(s)
  • jkoffman's Avatar
    08-27-2020, 07:23 PM
    Hi Kurt! Thanks for the confirmation that my pin choice was ok. I do have pin 0 connected to the reset pin, I also tried pin 1 just in case. I wasn't sure if there were limitations on the DC and CS combinations like...
    13 replies | 242 view(s)
  • jkoffman's Avatar
    08-27-2020, 04:50 PM
    Hi all, I'm trying my first ST7789 based LCD (320x240) with a Teensy 4.0 and I'm having a bit of trouble getting it to work. This is a generic LCD, nothing fancy. So far I've been unable to get anything to appear on...
    13 replies | 242 view(s)
  • jkoffman's Avatar
    08-27-2020, 02:58 PM
    Ok, I have done some tests, and here are my results! Since I have the two Teensys connected to two computers, I left DEBUG defined on both so I could get the serial output. When running both with just serial, one of...
    25 replies | 767 view(s)
  • jkoffman's Avatar
    08-27-2020, 01:27 AM
    Apologies for the delay, but I am back and sorting through things. I will try out that code as soon as I can. I'm hoping this eliminates the SPDIF hardware as the culprit and perhaps makes me focus more on the USB...
    25 replies | 767 view(s)
  • jkoffman's Avatar
    08-21-2020, 04:18 PM
    Not a rush, I'm slammed this weekend and won't have time to test anything until Monday at the earliest. It wouldn't surprise me if this was something on my end. What you're describing was basically what I did on my...
    25 replies | 767 view(s)
  • jkoffman's Avatar
    08-18-2020, 05:14 PM
    Nah, not only two connections but I wanted to clean up the wiring, get everything as short as possible to eliminate issues there, etc. I guess "tearing it apart" sounds a bit more intense than it was. It took about 5...
    25 replies | 767 view(s)
  • jkoffman's Avatar
    08-16-2020, 09:20 PM
    Sounds good. I am going to try tearing everything apart and starting again. Do you have any recommendations for the links between the two Teensys? Should I connect out->in directly, or put in a resistor, etc. ...
    25 replies | 767 view(s)
  • jkoffman's Avatar
    08-16-2020, 03:30 PM
    I did a bit more experimenting this morning. I still can't get the startup distortion to reappear. I'll keep trying to see if I can characterize that one better. On to the return path issue. I started by replacing...
    25 replies | 767 view(s)
  • jkoffman's Avatar
    08-16-2020, 02:58 AM
    I agree that it's weird i can't reproduce it. I'll try again in the morning to see if the computer it more likely to make it happen after having slept awhile. Honestly I have no idea why that would make a difference,...
    25 replies | 767 view(s)
  • jkoffman's Avatar
    08-15-2020, 04:02 PM
    Sounds good, I'm happy to follow any troubleshooting plan you're thinking of. You are correct on the setup. The noise/distortion is present when I first connect the sending Teensy. It persists for some time, though...
    25 replies | 767 view(s)
  • jkoffman's Avatar
    08-14-2020, 08:35 PM
    I hope I am able to explain this all clearly. I reverted to using spdif3 for transmit and spdif3_async for receive. I added the two tests you asked (more info later). I started with just the transmitter transmit...
    25 replies | 767 view(s)
  • jkoffman's Avatar
    08-13-2020, 07:34 PM
    Hi there, Thanks for the reply! I tried altering the anti-aliasing attenuation but I have the same issue. I added the debug code you had in the example file, and here is a sample of the output: buffered time :...
    25 replies | 767 view(s)
  • jkoffman's Avatar
    08-13-2020, 12:52 AM
    Well, I just had a bit of a disappointing test. I took two Teensy 4.0 boards, connected SPDIF in on one to SPDIF out on the other, and vice versa. I also connected ground together. Here's the audio setup portion of...
    25 replies | 767 view(s)
  • jkoffman's Avatar
    08-11-2020, 11:22 PM
    Thank you for the quick reply, and for reminding me of a few things! I completely spaced on the DAC thing, my mistake there. I can dispense with that part. I didn't realize that SPDIF on these chips doesn't use...
    25 replies | 767 view(s)
  • jkoffman's Avatar
    08-11-2020, 10:24 PM
    Hi all, I am planning on migrating my project to the Teensy 4, mostly for more power and greater flexibility with some interfaces. I'm trying to double check if various blocks will play nicely together. There...
    25 replies | 767 view(s)
  • jkoffman's Avatar
    08-09-2020, 03:45 AM
    jkoffman replied to a thread I2S Timing Issues in Audio Projects
    Just a quick update before I head to bed. I've been hacking away at these issues, and I've made a bit of progress. I've been working with @gfvalvo's BCLK = 64*Fs I2S blocks (available here:...
    2 replies | 191 view(s)
  • jkoffman's Avatar
    08-05-2020, 12:32 AM
    My issue was just that I was looking for documentation. speed12 pointed me the right way, so my current issue is solved.
    14 replies | 413 view(s)
  • jkoffman's Avatar
    08-04-2020, 11:21 PM
    jkoffman replied to a thread I2S Timing Issues in Audio Projects
    I should also mention that the system works fine when taking in audio through the audio board or through USB on the primary Teensy. It worked taking in audio from the secondary USB yesterday, but today it's crackly, and...
    2 replies | 191 view(s)
  • jkoffman's Avatar
    08-04-2020, 09:53 PM
    Hi all, I'm working on a project and seeing a weird intermittent problem. I'm trying to learn more about why it's happening so I can figure out a solution or at least a work around. This is a project with two...
    2 replies | 191 view(s)
  • jkoffman's Avatar
    08-03-2020, 07:55 PM
    @speed12 Ah thank you very much, that does help!!!
    14 replies | 413 view(s)
  • jkoffman's Avatar
    08-02-2020, 01:32 AM
    Hi all, I'm starting to play around with PlatformIO, and one thing I haven't found yet are the list of specific Teensy related platformio.ini options. For instance, I have been using USB Audio a bunch recently, I...
    14 replies | 413 view(s)
  • jkoffman's Avatar
    07-30-2020, 11:26 PM
    An interesting idea. I will have to experiment with it further. Though at one point I had pared things down to three objects and two patch cords, while only trying to change one of them. It still didn't work. Right...
    3 replies | 174 view(s)
  • jkoffman's Avatar
    07-30-2020, 01:05 PM
    A bit of further info: Adding the following code to the start causes the above code to fail: AudioInputAnalogStereo adcs1; //xy=214,270 AudioMixer4 mixer1; //xy=407,264...
    3 replies | 174 view(s)
  • jkoffman's Avatar
    07-30-2020, 04:02 AM
    Hi all, A while back I looked into creating dynamic patch cords to connect audio components. I wrote a simple test program that took USB audio in, connected it directly to line out, then swapped left and right...
    3 replies | 174 view(s)
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