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  1. And there's 20 years of scratching my head and...

    And there's 20 years of scratching my head and saying "why does this exist" resolved.
  2. What is your motivation to use HSV over RGB? I...

    What is your motivation to use HSV over RGB? I store everything as RGB (floats) and if I need HSV I have some code that converts the inputs to RGB. Same with input in Kelvin. Almost every effect I do...
  3. Is there a not too difficult way power could come...

    Is there a not too difficult way power could come from USB, or the other input if available, with automatic switching (like with a transistor) instead of cutting a trace?
  4. I was using int16_t for awhile, but eventually...

    I was using int16_t for awhile, but eventually switched to float as I wanted to be able to do more accurate brightness scaling and layering of effects. The possibility of storing negative numbers is...
  5. Interesting project. I notice the "$5" Pi Zero...

    Interesting project.

    I notice the "$5" Pi Zero is still never actually $5, or anywhere close to it, years after its release. That's too bad.
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    If you can derive the BPM using heuristics (or...

    If you can derive the BPM using heuristics (or know it up-front), and if the drums only hit at regular intervals, you could implement a timeout such that when a drum hit is detected it can't be...
  7. What is the significance of this? // Set the...

    What is the significance of this?

    // Set the PA Level low to prevent power supply related issues since this is a
    // getting_started sketch, and the likelihood of close proximity of the devices....
  8. Oh, okay, so you want sort of a U-shaped topology...

    Oh, okay, so you want sort of a U-shaped topology where it's reversing direction (maybe multiple times.)

    What he's doing is reversing the order of colors in every other row. In your example, you...
  9. It sounds like the Ethernet library is firing an...

    It sounds like the Ethernet library is firing an interrupt at the right interval to disrupt signal generation. OctoWS2811 uses DMA to talk to the LED arrays, so unless the bus is totally saturated...
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    The code I am using started in 2013 as a simple...

    The code I am using started in 2013 as a simple "read DS3231 clock and put some cool scroll text onto a 20x4 display" project, then evolved to support ATMega644, then again to support NeoPixels, then...
  11. The advantage of using multiple pins is that it...

    The advantage of using multiple pins is that it takes time to clock the colors down the chain of LEDs, and if one group of them is extremely long it can impact framerate. You are proposing to run...
  12. Off the top of my head, you are sending a float...

    Off the top of my head, you are sending a float into println() and getting "NaN".

    Try using Serial.printf("Sent temperature: %f\n", SENT_temperature). That way, you can eliminate "is println()...
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    It can work at 720p or 1280p, or whatever...

    It can work at 720p or 1280p, or whatever resolution you want, as long as the Teensy can go fast enough to keep up with the incoming data.

    I don't think you can count hsync pules, as they are only...
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    The point of using assembly instead of something...

    The point of using assembly instead of something else is to deal with situations where timing is critical. The WS281x driver for 8-bit Arduinos uses inline assembly, where the cycles consumed by each...
  15. That is interesting, as I have been writing code...

    That is interesting, as I have been writing code to do HSV and Kelvin conversions and the like. Does FastLED let you store color values as floats, and will it let you have negative numbers? I need...
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    I wonder if the optimizer turns the above code...

    I wonder if the optimizer turns the above code into 59 NOPs rather than emitting loop code wrapping a single NOP. I have found that when a loop does something that always necessarily comes out the...
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    Yes, if you wait for a vsync pulse you should be...

    Yes, if you wait for a vsync pulse you should be able to derive the exact pixel location simply by counting the pixel clock: row = (int)(pulses / width), column = pulses % width.

    Suppose you are...
  18. For some background, what exactly is the...

    For some background, what exactly is the difference between FastLED and OctoWS2811? I keep seeing FastLED mentioned but have no idea what it's for.

    I assume it plugs into OctoWS2811 at a high...
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    That is a phenomenal project. It's something that...

    That is a phenomenal project. It's something that should be in a parade.

    The T3.2 should be fast enough to do quite a lot with that. It hardly uses any CPU to drive the LEDs (just enough to...
  20. This shield seems like it has everything you'd...

    This shield seems like it has everything you'd want (except 3D and texturemapping), and the FPGA is pretty exciting. It will not ship for some time. Between now and then, there is some more silicon...
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    DVI will involve an I2C handshake, and then...

    DVI will involve an I2C handshake, and then reading the R/G/B data lines whenever the clock line transitions to the right state.

    Reading further into this, it's going to be a little tough. The...
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    Better that this should be provided directly by...

    Better that this should be provided directly by PJRC. You don't want to run binary code from some random person online. Even if the person is nice (and I suspect most people here are) there is no way...
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    I can see where you're going with that. One...

    I can see where you're going with that.

    One application that seems immediately obvious to me is CNC/3D printer controllers. One core speaks G-code, handles low-level I/O, generates steps, reads...
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    There has to be a way to write normal threaded...

    There has to be a way to write normal threaded code in a single program, rather than having two distinct programs.

    If the first core can upload code to the second core's flash, or to its RAM (and...
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    Echoing the others in this thread who are calling...

    Echoing the others in this thread who are calling for USB-C. Micro-USB cables are annoying and failure-prone.

    I would further request that power delivery is supported, to as many watts as...
  26. I think you need somewhere around 100MHz for...

    I think you need somewhere around 100MHz for this. TI has one that will do up to 70MHz and it's less than a buck.
  27. If you're worried about power consumption, the...

    If you're worried about power consumption, the Teensy 4.x has several "low power" modes, as detailed here: https://www.nxp.com/docs/en/application-note/AN12085.pdf

    It can wake on interrupt or...
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    I designed a carrier that fits Teensy 3.2 and...

    I designed a carrier that fits Teensy 3.2 and 4.0. The board is constrained on three sides by the carrier, and on the fourth side by the enclosure. The carrier is bolted to the enclosure, so it's not...
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    That is really cool! I love NeoPixels, but I know...

    That is really cool! I love NeoPixels, but I know where you're coming from. At low brightness, you can definitely notice discrete levels of illumination.
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    That depends greatly on the microcontroller, bus,...

    That depends greatly on the microcontroller, bus, and signaling protocol. If there are data + clock lines, then you can have as many bits per second as states (low or high) per second. On the other...
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    When I wrote a driver that needed...

    When I wrote a driver that needed 400-nanosecond-wide pulses, I generated a waveform in RAM and used DMA to transfer it to the PWM generator. The 'scope demonstrated that it was quite accurate. It...
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    "500 PM2.5... Not great, not terrible..."

    "500 PM2.5... Not great, not terrible..."
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    VGA would be fairly simple, as it's analog,...

    VGA would be fairly simple, as it's analog, although if you're interested in individual pixels you will have to track the rasters and then sample at just the right moment.

    With DVI, you will have...
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    I am seeing CO2 PPM counts well over 800 in Los...

    I am seeing CO2 PPM counts well over 800 in Los Angeles. Normally it would be less than 500.
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    If the HDMI signal is content-protected (look up...

    If the HDMI signal is content-protected (look up HDCP), you will not be able to get anything out of it without a decoder that has whatever officially licensed tech is necessary to decode the stream....
  36. A shift register would work fine with encoders,...

    A shift register would work fine with encoders, if it was sampled fast enough. You would have to poll it continuously, or you'd miss pulses. How frequently depends on how many pulses per revolution,...
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    This is the line I was talking about: ...

    This is the line I was talking about:


    #define SetSPISpeed 47000000 //F_BUS/3 47000000 (47 MHz) Teensy 4
    The comment says where it comes from, but it's still a hard-coded literal. If the...
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    That code looks like it assumes something about...

    That code looks like it assumes something about F_BUS, which might be right, but if you change the clock speed it probably breaks this. It looks like a code smell to me.

    These libraries may have...
  39. Shift registers (such as port expanders) will...

    Shift registers (such as port expanders) will work with Teensy just as well as they would with any other microcontroller, assuming they have the same interface. Some are SPI, some are I2C, and some...
  40. I guess anything can be used as a serial port, if...

    I guess anything can be used as a serial port, if you want to try hard enough. The simplest method of communication is I2C (two wires, sorta fast) followed by SPI (three or four wires, pretty fast.)...
  41. "GPIO expander" is another way of saying "two-way...

    "GPIO expander" is another way of saying "two-way shift register." Those are always purely digital. Each line is a single bit, so it can only be 1 or 0. It is possible to have some Rube Goldberg...
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    Teensy pinouts can be found here:...

    Teensy pinouts can be found here: https://www.pjrc.com/teensy/pinout.html

    All those pins seem to do with SPI, which would not be useful for connecting a joystick over USB. However, for talking to...
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    115200 is a typical UART speed that you will see...

    115200 is a typical UART speed that you will see in old-fashioned serial devices, primarily modems and ISDN terminal adapters. SPI doesn't adhere to that exact speed. I think it will run as fast as...
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    I always thought "long long" should have been...

    I always thought "long long" should have been called "extremely long" instead.
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    You could get really fancy and use an...

    You could get really fancy and use an opto-coupler.
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    How come the code is in both French and Spanish?...

    How come the code is in both French and Spanish? :confused: ;)

    I don't see why both devices can't play nice on the same bus, as wired. I think that should be fine. You might want to check the...
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    Best way to reboot Teensy 4.x?

    I read in this thread that you can reboot a Teensy 3.2 by writing something to a register. Is that still the right way to do it for the 4.x series? If so, what's the code to do that?

    I also saw a...
  48. Based on that pinout chart, it looks like the ESP...

    Based on that pinout chart, it looks like the ESP supports SPI and I2C. If you can't get serial running, my next bet would be either of those. Failing that, you could talk directly over GPIO,...
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    You can get an ATAPI to USB adapter for $30:...

    You can get an ATAPI to USB adapter for $30: https://www.amazon.com/gp/offer-listing/B00NJ5CZJC/ref=dp_olp_unknown_mbc

    Of course, that means you don't have a cool project; so if you want a cool...
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    Arduino devs often stay away from String because...

    Arduino devs often stay away from String because it allocates and frees memory. Over time, this can cause memory fragmentation where the largest available contiguous block shrinks over time, and...
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