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Type: Posts; User: Rena

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    Of course, that should have been obvious. Thanks!

    Of course, that should have been obvious. Thanks!
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    Correct way to read RTC registers?

    The register `RTC_TSR` contains the counter in seconds, and `RTC_TPR` contains fractional seconds, but what's the proper way to read both? If I read one and then the other, it's possible the TSR...
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    If the CPU truly reaches 500 degrees, that's very...

    If the CPU truly reaches 500 degrees, that's very impressive... it can get quite hot to the touch if running at full speed constantly with no idling, but this is normal. Your programs should avoid...
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    Yes, if you cut that bridge, the Teensy won't...

    Yes, if you cut that bridge, the Teensy won't draw any power from the USB port (you'll have to provide it to VIN some other way). Or if you solder a USB cable directly to it, you'd have to leave off...
  5. Thread: I2C maximum speed

    by Rena
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    I2C can be pretty finicky. In your graph it looks...

    I2C can be pretty finicky. In your graph it looks like you have some bus capacitance which will interfere with the signal.
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    Yeah, I'll order the proper ones, but I was...

    Yeah, I'll order the proper ones, but I was hoping to get this working quickly.
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    The package doesn't say much useful: I...

    The package doesn't say much useful:



    I could add a capacitor, but I'm not sure where or what capacitance. I tried messing with the RTC_CR_SCxP bits but they didn't help.
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    RTC only counts when I touch the device

    I've added a crystal to a Teensy 3.2, but the RTC only advances if I touch some parts of the Teensy with my finger. I've resoldered it, and it doesn't happen if I touch with plastic, so what's going...
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    Alright, I put that circuit together on a...

    Alright, I put that circuit together on a breadboard and it seems to do the job. Is there an IC that combines several of those circuits?
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    Protecting analog inputs from overvoltage

    As I understand, the analog inputs on Teensy 3.2 are rated for 3.3V maximum and can't handle a 5V input. In my project I want to defend against accidentally connecting a 5V source.

    I've found this...
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    Ahh, that explains a lot. I did manage to...

    Ahh, that explains a lot.

    I did manage to improve performance quite a bit though with a few tweaks. I found that using GPIOx_PTOR instead of the bit-band version is much faster, and unrolling...
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    I did some benchmarking and I'm not getting...

    I did some benchmarking and I'm not getting anywhere near that. At 72mHz, using the display in landscape mode (480x320 resolution, 16 bits per pixel):


    Clearing to a solid colour, where both...
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    I'm actually using a library I made from scratch....

    I'm actually using a library I made from scratch. It does also optimize digitalWrite to a single memory write.
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    Unfortunately all 8 data bits are needed to send...

    Unfortunately all 8 data bits are needed to send commands during initialization. Maybe I could physically switch the wires around afterward...

    I was looking at using DMA, but I'm not sure how I'd...
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    Any way to remap GPIOs?

    I'm using Teensy 3.2 to drive an ILI9481 TFT LCD on a breakout board. The protocol for transferring image data (after initialization) is pretty simple: you send X, Y, width, height, and pixel data...
  16. Thread: More RAM?

    by Rena
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    Well, there were a few. One project I've been...

    Well, there were a few.

    One project I've been working on is modding a PSP. With software modifications I can remove the disc drive and just run games from the memory card. That frees up a bit of...
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    Invalid URL on store cart page

    Add some items to your cart from https://www.pjrc.com/store/teensy32.html .
    Click "Convert to a different currency (popup)."
    Popup displays an "Invalid URL" error.
  18. Thread: More RAM?

    by Rena
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    More RAM?

    Wondering if it is or might become possible to get a Teensy 3.2 with as much as 8MB of RAM? That would be very useful for some of my projects where adding external RAM is not as practical.
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    Alright, that's no problem. I'm just unsure about...

    Alright, that's no problem. I'm just unsure about point 2:



    Does that mean my code has to support all Teensy devices? Right now it only supports 3.1 (and 3.0, but that isn't tested).
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    Like I said, it's mostly for fun. I like working...

    Like I said, it's mostly for fun. I like working with bare metal. That said, I've still copied a lot of the Teensyduino code. :p

    Teensyduino itself is great code; my only gripe is that it seems...
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    I see. Thanks a lot! Is there an official IRC...

    I see. Thanks a lot!

    Is there an official IRC channel for Teensy? I feel like that might be more convenient for these discussions. :)
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    Aha, so I'd only use that if I were unsure of the...

    Aha, so I'd only use that if I were unsure of the pullup states?

    Thanks for all the help and fast responses!
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    Ahh, I didn't realize those functions existed. Is...

    Ahh, I didn't realize those functions existed. Is there any reason to *not* use the fast versions? It seems like the huge if/else chain would all get folded down to a single statement at compile...
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    Cool, thanks! I have been using the Arduino...

    Cool, thanks!

    I have been using the Arduino IDE for a while, so I know the hardware works well. Mostly I just wanted to be able to work entirely on the command line, and write "bare metal"...
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    Using Teensy 3.1 without Arduino

    Has there been any development on programming Teensy 3.1 directly in C, without the Arduino/Teensyduino libraries/GUI? I've only seen the Blinky example for Teensy 2.0; the page says it doesn't apply...
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    I think it's largely because of abstraction....

    I think it's largely because of abstraction. Modern programs are bigger, but they do a lot more. Sure back in the 80s, we could fit a word processor in 64K, but it only worked on one specific model...
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    Simulating multiple USB devices (Teensy 3.1)

    I have the Teensy 3.1 that I've been programming using the Arduino software. I've been able to connect several Nintendo controllers and have it read them. Now for the next step of my project I want...
  28. hid_listen not working on Linux (waiting for device)

    I'm unable to get the hid_listen program to work on my system (Lubuntu 13.10 on AMD64). Even when run as root, it never gets past "waiting for device". The serial monitor in the Arduino program does...
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    Alright, well after a bunch more probing and...

    Alright, well after a bunch more probing and examining the code I got it working! :D

    The first major issue was that the port mode registers don't work the way I thought, so I was never actually...
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    Reading an N64 controller, getting no data

    I'm trying to read an N64 controller using the Teensy 3.1. I'm not very knowledgeable about low-level electronics and serial ports but I think I have the basic protocol down right.

    The N64...
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    Aha, thanks. I'm trying now to build gcc for...

    Aha, thanks.

    I'm trying now to build gcc for the Teensy 3.1 so I can compile for it and do everything from the command line, without using that buggy Arduino IDE that doesn't want to resize its...
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    Teensy CLI loader with Teensy 3.1

    Just wondering, the CLI loader only appears to understand the MCUs "at90usb162", "atmega32u4", "at90usb646", "at90usb1286" and "mk20dx128". But isn't Teensy 3.1 using mk20dx256? Is the program out of...
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