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  1. S

    T4 overheats when connected to my PCB

    Well, I think I learned an important lesson—The TLC5940s simply produce a massive amount of heat! I didn't see any hotspots on the Teensy itself...the TLCs however slowly warmed the entire board. It still doesn't make sense to me how the Teensy can reach an internal junction temp of 90C from...
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    T4 overheats when connected to my PCB

    Ah! The board outline I shared is of a later revision, where I flipped that around. Here's the correct outline for this board: I'm using NMOS, N7000, so I think it should be correct, no?
  3. S

    T4 overheats when connected to my PCB

    PDF attached. Yes, at 12V input I was at 100 mA and the Teensy was running at 85C and climbing. It's a very slow temp creep, over 10 minutes it goes from room temp to 90C. Right now it's a 5V converter. I know it should be 3.3v, I recently changed my board from T3.2 to T4.0 so the 3.3v...
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    T4 overheats when connected to my PCB

    All great questions! I've attached the schematic. The reason I included the PCB was because I suspect this is a physical heat transfer issue, not a circuit thing. For instance, when I raise the Teensy off the board with a set of headers, the temp definitely drops. When I set the TLC5940 outputs...
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    T4 overheats when connected to my PCB

    I have a real puzzler here. I have a PCB board designed with a few TLC5940 chips daisy-chained to a T4. I've used these boards many times before. When run on the board, the Teensy gets extremely hot. According to tempmonGetTemp(), the internal junction temperature reaches 90C. Now here's the...
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    TLC5940 Updated Library for Teensy 4.0: Multiplexing and Temporal Dithering

    Who doesn't like an update?! This new version doubles the operating frequency of the TLC to 8 MHz, which increases functional brightness and also allows what is now 16 (!) levels of temporal dithering.
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    Teensy 4.1 powered from both the USB cable and VIN.

    To answer this part of your question, no, the risk of damage is low. USB ports on laptops are traditionally protected from overvoltage, I think up to something like 21V. I've been working this way for close to 10 years with my laptop and benchtop supply connected simultaneously and never had an...
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    Sparkfun Tlc5940 and Teensy 4.0

    This is great. The current library runs the TLC at 4 MHz and when I tried to double the frequency I encountered this overshoot. I'll have to try adding the resistors!
  9. S

    Sparkfun Tlc5940 and Teensy 4.0

    Actually, this sounds possible, I remember now having some similar issues while breadboarding with the TLC5940 using longer jumpers. Worth a shot.
  10. S

    Sparkfun Tlc5940 and Teensy 4.0

    This is very odd, because I too have designed a custom board for up to 16 chained TLC5940 with the T4.0, I've constructed this board twice with up to 8 chips populated and it works great. I assume if you are using T3.2 and T4.0 on the same board you are making some modifications to move the...
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    Sparkfun Tlc5940 and Teensy 4.0

    I have had bad experiences with this breakout board. Almost immediately after using it it became defective. Your problem sounds a lot like a bad connection, but maybe on the Teeny side since it works well with T3.2. Very mysterious but certainly a hardware configuration issue.
  12. S

    Can you damage a Teensy by changing its timers?

    I'm playing around with FlexPWM and suddenly despite reverting all changes to my library back to the last working version it's not working right. I've tried rebooting and resetting already. I can't tell what's gone wrong, but there is all sorts of flickering on my outputs. What did I do?
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    Help me optimise this code

    Just out of curiosity, have you tried asking openAI for suggestions on how to optimize it? That seems like it would be one of its ideal intended purposes.
  14. S

    Teensy Loader / PlatformIO Compatibility Issue

    Honestly if you do a lot of work with Teensy, you should buy a cheap Windows laptop to use Visual Micro. No, there isn't a Mac version, but it is hands-down the best coding environment. You can still set up Microsoft Remote Desktop to access it from your Mac. It's latency-free and the...
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    Using ChatGPT / OpenAI for Arduino help

    Incredibly, if you simply ask it "Are you sure?" it will return a (more) correct answer, with an apology for the previous mistake. You can even ask it to double-check its answers before it sends them to you in the future. It's already been indispensable in my work. I've asked it to help me...
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    Can no longer upload to Teensy 4.1 via PlatformIO or Arduino IDE

    +1 for Visual Micro. I just got it up and running for the first time a few days ago and it is life-changing.
  17. S

    TLC5940 Updated Library for Teensy 4.0: Multiplexing and Temporal Dithering

    I wanted to share this library that takes previous work by Alex Leone and Paul's updates to add Teensy compatibility, and adds functions such as 3-column multiplexing and temporal dithering. I won't say it improves it, because it won't be ideal for every project. But if you're driving RGB...
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    What just happened? Teensy 4.0 blinks red four times, now dead

    Thanks Paul, I was able to recover one of them using your information. Three of them are still dead (not showing 3.3v). I can attribute two of them to accidental swipes of 12v wires, but the one that had the flash memory error remains a mystery as to why that zonked out. I have quarantined the...
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    Data types: Which should I be using?

    I'm doing some simple raytracing on the Teensy 4.0. That means doing a lot of dot products of normal vectors, so lots of decimals with values from -1 to 1. I've been using single-precision floats, but I don't think this is the best choice, as I'm seeing a lot of flickering and "stepping" as the...
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    What just happened? Teensy 4.0 blinks red four times, now dead

    Another Teensy dead. This time I pressed the Program button and it was one long red, on and off. Reconnected it and now it's no LEDs, totally dark, dead and Windows says "USB device has malfunctioned." I'm grounding myself every time I touch the thing. I've triple checked my circuit. I don't...
  21. S

    What just happened? Teensy 4.0 blinks red four times, now dead

    Irrecoverable I'm guessing? Not sure what I did. Would electrostatic damage be a reasonable hypothesis, or just a bad unit? Just want to make sure when I plug in a new one I'm not going to fry that one too.
  22. S

    What just happened? Teensy 4.0 blinks red four times, now dead

    I have been using my Teensy with USB cable without issues. Today I booted up and the Teensy blinks red four times, pause, blinks four times, etc. I held the program button for 15 seconds and the blinking stopped, but the Teensy is still not responding or being recognized by the computer. What...
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    Teensy 4.0 and TLC5940 compatible?

    Paul, thanks for double-checking this. Seeing your reply assured me it was a physical problem and I was able to try again using a new board that came in today with the proper 4.0 footprint, and indeed, the problem has resolved. It must have been a weak connection somewhere. Thanks again and...
  24. S

    Teensy 4.0 and TLC5940 compatible?

    Or maybe it has nothing to do with GSCLK moving around. Despite adding a line to reset the timer counters, now all the pulses are aligned, but the odd behavior hasn't changed. I feel like it has to be something in the Tlc.update function that is doing something wonky. I'm beginning to realize...
  25. S

    Sparkfun Tlc5940 and Teensy 4.0

    Hi seblanc, did you ever get this to work with 4.0? I'm experiencing a similar issue.
  26. S

    Teensy 4.0 and TLC5940 compatible?

    The random change in output levels looks similar to the problem described by this person. https://forum.pjrc.com/threads/71009-Sparkfun-Tlc5940-and-Teensy-4-0 I've probed the outputs while the Teensy 4.0 is isolated from the circuit and the scope looks the same. GSCLK experiences a floating...
  27. S

    Teensy 4.0 and TLC5940 compatible?

    No observable change in behavior with added ground wires. What could cause the GSCLK timer to shift like that?
  28. S

    Teensy 4.0 and TLC5940 compatible?

    Paul, digging into this more using the scope, take a look. I think this is interesting. GSCLK has a different timing and wagging out of sync all over the place on the Teensy 4.0 Teensy 3.2: Teensy 4.0:
  29. S

    Teensy 4.0 and TLC5940 compatible?

    By all means please take a look...on the bottom is my board which is designed for 3.2, going to 4.0 via the jumpers. For what it's worth, The Tlc.get command returns the correct values. Not sure how the library works, if it's pulling those values from the chip or not.
  30. S

    Teensy 4.0 and TLC5940 compatible?

    Hi Paul, happy new year. I'm getting some very odd behavior with the TLC5940 on Teensy 4.0. I've checked I'm using the latest 0.16 library. This is my simple code to generate white light from an RGB LED using three channels. My circuit works flawlessly with a Teensy 3.2. When I use a Teensy 4.0...
  31. S

    digitalWrite doesn't work inside library?

    Never mind, solved
  32. S

    Help with hardware interrupts on 3.2

    Thanks! In regards to that easier method, is there a reason I have to tie it to a separate pin and attach the interrupt to that one, instead of using attachInterrupt on the XLAT or BLANK output pin directly?
  33. S

    Help with hardware interrupts on 3.2

    Yea, I was investigating attachInterrupt. Seems like it might work, but I would sure like to solve the “right” way to do it. It feels like I’m close! but maybe not. Can you verify my understanding of those couple lines of code inside the ftm1_isr(void) function? sc & 0x80 is the overflow flag...
  34. S

    Help with hardware interrupts on 3.2

    Hi Paul! Just the man I want to ask. Sorry if I wasn't clear enough, I'm trying to add support for multiplexing; I have the rows connected so they can be enabled individually, and I want to trigger a row change on every XLAT/BLANK clock pulse. A few other people had success with this years ago...
  35. S

    Help with hardware interrupts on 3.2

    I'm trying to write my own multiplexing code for the Tlc5940 for Teensy while looking at previous attempts by others on Arduino/AVR and need help converting some interrupts to ARM. I think I'm close, but I don't have any experience with interrupts and am a little out of my depth. The basic gist...
  36. S

    Teensyduino no longer finding libraries?

    I opened up Teensyduino today and I'm getting errors like "arm_math.h: No such file or directory" When I try to compile. Supposedly this is a library that is included with Teensyduino, and it was compiling fine yesterday. I get the same errors for all the other libraries I'm trying to use...
  37. S

    Teensy 4.0 and TLC5940 compatible?

    I see the TLC5940 library is compatible up to Teensy 3.6. Is it compatible with 4.0? I'm still getting familiar with it, but the pinouts and SPI seem radically different from 3.x, and can't tell if it'll work with the libraries as-is. Hoping for some clarification on compatibility. Thanks.
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