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Forum Index : Microcontroller and PC projects : Bug in RGB() command?
| Author | Message | ||||
| George H Newbie  Joined: 03/07/2020 Location: United StatesPosts: 24 |
PicoMite MMBasic Version 5.07.08b9 Option Colourcode On It seems the computed values for red and green are swapped. Or could it be board specific? RGB(255, 0, 0) lights the led green. RGB(0,255,0) lights it red. Using the Waveshare RP2040-Matrix board. |
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phil99 Guru  Joined: 11/02/2018 Location: AustraliaPosts: 2136 |
No problem on any of my displays, must board specific. What display controller chip does the LCD use? Check the manual to see if there are special settings for it. |
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| George H Newbie Joined: 03/07/2020 Location: United StatesPosts: 24 |
It's the WS2812. With a 1-wire interface, not sure how it could be wired wrong - I can work around it but it's strange. |
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TassyJim Guru Joined: 07/08/2011 Location: AustraliaPosts: 6100 |
5.07.08b11 My WS2812 gives the correct colours. A single chip. Mine needs type O and if I use type B, all I get is white. It also works correctly on much earlier firmware. Try both WS2812 types. Jim VK7JH MMedit MMBasic Help |
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Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6798 |
Of course, there's no guarantee that they have used the same version of the WS2812 that we know. There may be other variations. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 9126 |
This is a classic symptom of incorrect WS2812 timing and nothing to do with the RGB command. As others have said try the different variants and if nothing works then your LED is perhaps faulty of a new variant that the firmware doesn't understand |
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| George H Newbie Joined: 03/07/2020 Location: United StatesPosts: 24 |
Tried both types (B and O) and same behavior. Found another WS2812 and behavior is normal so I guess it's these little Waveshare boards. |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 9126 |
Which board? Please post link. Did you try "S"? Edited 2023-08-22 04:32 by matherp |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6798 |
This one: LINK SCHEMATIC Says it's a WS2812B, but has a mosfet level shifter. I don't know when the change happened, but at one point the reset pulse time was lengthened from >50us to >280us. That breaks things sometimes. Link . Edited 2023-08-22 04:49 by Mixtel90 Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| barewires Newbie Joined: 13/04/2015 Location: United KingdomPosts: 30 |
[code] #waveshare rp2040-zero-GRBblack-blink.py #MicroPython v1.19.1-879-g294098d28 on 2023-02-20; Raspberry Pi Pico W with RP2040 #by chatgpt and RS 25022023 import machine import neopixel import utime # set up neopixel LED NUM_LEDS = 1 np = neopixel.NeoPixel(machine.Pin(16), NUM_LEDS, bpp=3) green = (128,0,0,255) red = (0,128,0) blue = (0,0,128) black = (0,0,0) def doneopixel(color): np[0] = color # set LED color np.write() # update LED utime.sleep(.1) # main loop while True: # generate RGB color color = red doneopixel(color) color = green doneopixel(color) color = blue doneopixel(color) color = black doneopixel(color) utime.sleep(1.1) [/code] |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6798 |
This is about as simple a test as you can get to identify the LED colours in normal MMBasic. It should work aas expected with standard WS2812B and WS2812 (by changing the B to O). I've not tested this, by the way. do bitbang ws2812 b, gp12, 1, &hCC0000 'red pause 500 bitbang ws2812 b, gp12, 1, &h00CC00 'green pause 500 bitbang ws2812 b, gp12, 1, &h0000CC 'blue pause 500 loop This data sheet indicates that the display order is GRB, not RGB. Note that this data sheet predates the change to >280ms reset time (LINK). MMBasic appears to swap R and G values to make the command compatible with the RGB(rr,gg,bb) format. (I thought this site was interesting.) Edited 2023-08-22 18:16 by Mixtel90 Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 9126 |
Looks like there is a new variant of the WS2812B, I'll increase the reset pulse in the next beta |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6798 |
I've not managed to find a newer data sheet. I found a link, but it's dead. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| George H Newbie Joined: 03/07/2020 Location: United StatesPosts: 24 |
Yes, that's the board I'm using, sorry. They were posted up here a while back. Thanks for sleuthing the details, Mick. |
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| George H Newbie Joined: 03/07/2020 Location: United StatesPosts: 24 |
Thanks Peter, when the next release is available I'll give it a try and report back. Edit: tried 'S', no change. Edited 2023-08-23 09:21 by George H |
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| George H Newbie Joined: 03/07/2020 Location: United StatesPosts: 24 |
Mick that test gives the same green/red swapped behavior as before. Also, seems to make no difference whether I use O, S, or B. I can report that the little board overclocks nicely to 376Mhz. |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6798 |
T thought it would as it's using the MMBasic RGB translation rather than controlling the WS2812 directly, which would, apparently, use GRB according to the data sheet. It seems odd that using a "conventional" WS2812B under MMBasic is fine yet this board isn't. The WS2812B's RGB order hasn't changed AFAIK so I can only think that it's a timing issue with those particular devices. . Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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