Hi,
first of all, i know what you mean with:

/*
This table contains the available pins and their corresponding SERCOMs and
DMA-related registers and such. M0 can actually handle SPI DMA on more
pins than are indicated here, but the code design INTENTIONALLY limits it
to specific pins. This is not a technical limit, but a documentation issue.
There are usually multiple pins available for each SERCOM, but each SERCOM
can have only one active MOSI pin. Rather than try to document "If you use
in X, then pins Y and Z can't be used" (and repeating this explanation for
up to four SERCOMs, and that the specific pins can vary for each board),
it's 10,000X SIMPLER to explain and use if one specific pin has been
preselected for each SERCOM. I tried to pick pins that are nicely spaced
around the board and don't knock out other vital peripherals. SERCOM pin
selection is NOT a fun process, believe me, it's much easier this way...
*/

SERCOM <> PIN-relations described here:
https://learn.adafruit.com/using-atsamd21-sercom-to-add-more-spi-i2c-serial-ports/creating-a-new-spi

is it possible to add a new constructor(?) (for experienced user) with sercom and pin parameters, so user can define his own sercom/pin configuration?

e.g. instead of:

Adafruit_NeoPixel_ZeroDMA strip(NUM_PIXELS, PIN, NEO_GRB);
something like that:
Adafruit_NeoPixel_ZeroDMA strip(NUM_PIXELS, &sercom5, SERCOM5, SERCOM5_DMAC_ID_TX, A5, 6, 7, SPI_PAD_0_SCK_3, SERCOM_RX_PAD_2, PIO_SERCOM_ALT, NEO_GRB);

another possibility to define sercomTable[] in a user sketch instead of library and use it (pointer ?) for sercom-definition.

Another question: for example user uses A5 for MOSI, pins 6 and 7 are used for MISO and SCK, that also means, that user can't use pins 6 and 7 for other stuff (like digitalWrite), right?

I looked through the available source, but I couldn't find a license.

Have I missed something obvious?

Hy

I am using an Arduino Nano 33 IoT with Adafruit neopixel side leds together with an RGBW neopixel stripe and some servos.
The servos trembled when using the "ordinary" neopixel library. Fortunately I found your solution with ZeroDMA. Unfortunately, it does not work with two objects of stripes. Even the pin asignement goes wrong.
I use pins 4 and 7.
If I only use one object, everything goes right for both pins. Only in combination with two objects it does not work.

The NeoPxl8 library I cannot use because I have two different types of neopixels.

Mixing one DMA object with objects from the "ordinary" neopixel library works. But makes no sense. Servo will tremble again.

I really like Adafruit products and bought already a lot of them. I kindly hope Adafruit/someone will find a solution, soon. Also because you wrote, that it theoreticaly should work.
I am also willing to test your solution as soon you have.

If you are doing some work here: My modifyable code plans to update the numbers of pixels, RGB type, etc. AFTER the initialisation of the objects. So the up to now missing update-functions would also be very helpful for me if someone implement them.

Thanks a lot and kind regards
Silvan

So this uses DMA , using SPI , right ?
So can i use my WifiNina library next to it without weird conflicts ? (because i think it talks over SPI also)

And i am trying to find my pinout.
I have this data now :
-The SAMD21 MCU has 6 SERCOM based SPIs. SERCOM1 is available on pins 1, 14, and 15.
-Metro M0 or Arduino Zero: pins 5, 12 and MOSI*.
-the new Nanos have pin mapping similar to classic Nano. so SPI is on pins 10,11,12,13
PIN MKR PIN PIN DESCRIPTION
| 22 | 1 | PA12 | NINA_MOSI
| 23 | 2 | PA13 | NINA_MISO
| 24 | 4 | PA14 | NINA_CS
| 25 | 3 | PA15 | NINA_SCK
Which one , would be my pin , that i use ??

I have had good success using this library with a Nano 33 IOT BLE, it solved the interrupt problem and works great, once again thank you for developing it.

i used the this lib #include <Adafruit_NeoPixel.h> and used the simple example i managed to get an green led on pin 6.

when i switch to this lib#include <Adafruit_NeoPixel_ZeroDMA.h>
i start the strand example. on pin 5 - Serial.println(strip.begin())gives me 1.
but icant see a light

Thank you for this interface. Just started using this great library, really saved me a lot of time. I'm getting a compiler warning, all seems to be working but would like to see if it could be fixed.

Warning:

c:/users/dmyty/appdata/local/arduino15/packages/arduino/tools/arm-none-eabi-gcc/7-2017q4/bin/../lib/gcc/arm-none-eabi/7.2.1/../../../../arm-none-eabi/bin/ld.exe: warning: changing start of section .bss by 8 bytes

Using:

Version: 2.2.2-nightly-20231224
Date: 2023-12-24T03:10:39.626Z
CLI Version: 0.35.0-rc.7

Copyright © 2024 Arduino SA

Includes are:

#include <ArduinoBLE.h>
#include <Adafruit_NeoPixel_ZeroDMA.h>

Thank you again for all you do.

Hi @ladyada
a made a PR #5 with a flexible begin function to define own pins.
Since this #10 this function is private :/

Why did you made it?

Does not compile for Seeeduino Xiao M0 (SAMD21) due to this #ifdef not catching the Xiao type:

#ifdef ARDUINO_SAMD_ADAFRUIT
typedef SPIClass SPIClassSAMD;
#endif

The Xiao board library uses SPIClass and not SPIClassSAMD.

After commenting out the ifdef and endif to test, the Xiao crashes. I would love to use this library on the Xiao M0 but I'm not smart enough to modify it myself. Any help would be appreciated!

I had to ditch the usual Adafruit_NeoPixel library for my project so I tweaked pins.h, adding for ADAFRUIT_QTPY_M0:

&sercom3, SERCOM3, SERCOM3_DMAC_ID_TX, 11, SPI_PAD_2_SCK_3, PIO_SERCOM_ALT,

to the sercomTable[] values. Now I can DMA drive the NeoPixel without interfering with my code (see context).

Running Adafruit_NeoPixel_ZeroDMA on an Adafruit Metro M0 causes the board to crash (main loop stops, USB goes away).

Running versions:

v1.04 Adafruit DMA neopixel library
v1.1.6 Adafruit Neopixel library
v1.0.1 Adafruit Zero DMA library

The following causes the issue (using the on-board NeoPixel of the Metro M0 Express)

#include <Adafruit_NeoPixel_ZeroDMA.h>
Adafruit_NeoPixel_ZeroDMA strip(1, 40, NEO_GRB);

void setup() {
strip.begin();
strip.setBrightness(32);
strip.show();
}

void loop()
{
strip.setPixelColor(0,125,125,0);
strip.show();
delay(2000);
strip.setPixelColor(0,125,0,125);
strip.show();
delay(2000);
}

I get this error when compilig the strandtest example with 1.0.8. I was trying to use the Metro M4 board and the on board neopixel. This error goes away if I roll back to lib version 1.0.7:

error: 'class Adafruit_ZeroDMA' has no member named 'isActive'

 while(dma.isActive()); // Wait for DMA callback, so pixel data isn't corrupted