Update rmt translator #3629
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Update rmt translator #3629
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The number of buffers required for optimal operation should be selected by the ws2812 module, not the caller.
This patch adds compatibility for different RGB LEDS besides the WS2812. ESP evaluation boards like the ESP32-C3-DevKitM-1 use an SK68XXMINI-HS RGB LED which does not respond to the timings of this module. The patch adds optional parameters for the bit timings to the write function. If the new parameters are not supplied, the old values are used. An example for the SK68XXMINI-HS is provided in the documentation.
The old RMT translator was not able to split the bits of the source data into the size requested by the RMT transmitter. Either all 8 bits of an input byte were translated or none. The new routine removes the restriction by delivering exactly the requested amount of data to the transmitter, which results in a more balanced buffering of translated data under load.
This patch introduces a new optional parameter for the reset time in the RGB LED communication. The default is 51.2 microseconds. A value of 0 sends no reset signal, which allows a small optimisation for consecutive write commands. Please note that the reset time of the old code should be 50 microseconds, as the define WS2812_DURATION_RESET suggested. Due to the restrictions of the old RMT translator routine, it was slightly increased to 51.2 microseconds. This patch keeps the value of 51.2 microseconds to be as compatible as possible.
Place all RMT channels in a group to minimize the time drift between the signals. Please note that this feature is not available on all platforms.
4 tasks
pjsg
reviewed
Feb 4, 2024
pjsg
reviewed
Feb 7, 2024
docs/modules/ws2812.md
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| @@ -44,6 +52,10 @@ ws2812.write({pin = 4, data = string.char(255, 0, 0, 255, 0, 0)}, | |||
| {pin = 14, data = string.char(0, 255, 0, 0, 255, 0)}) -- turn the two first RGB leds to green on the first strip and red on the second strip | |||
| ``` | |||
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| ```lua | |||
| ws2812.write({pin = 8, reset = 800, t0h = 3, t0l = 9, t1h = 6, t1l = 6, data = string.char(1, 0, 0)}) -- turn the SK6812 RGB led on the ESP32-C3-DevKitM-1 to green | |||
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Does this work -- I would have thought that using 255 as the intensity rather than 1. Also, what is the color ordering for the SK6812? You set the first value to get green, which implies that it isn't RGB.
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The SK6812 is a very bright LED. A value of 1 is clearly visible. Setting it to 255 was painful for my eyes.
You are correct, the color ordering is really green - red - blue, see end of page 6 in the data sheet here. Thanks, the patch is updated.
However the WS2812 has the same color ordering (see here, page 5). The APA104 is the only LED in the list using RGB color ordering (see here, page5). The current documentation uses the term "RGB" or "RGBW" for all of them:
Send data to up to 8 led strip using its native format which is generally Green,Red,Blue for RGB strips and Green,Red,Blue,White for RGBW strips.
If you agree that this is a bit confusing I will open a new ticket for it.
The SK6812 expects the data for the green LED first, then red and finally blue. It should be described as a GRB LED.
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Fixes #3628 .
dev-esp32branch rather than for thereleasebranch.docs/*.This set of patches adds optional parameters to the WS2812 module to set the duration of the reset signal and the duration for the high and low phase of the 0 and 1 symbols. This allows to control many other RGB LEDs besides the WS2812.
The main intention of this patch is to control the RGB LED of the ESP32-C3 dev kit.