Disassembled and successfully flashed an openbeken firmware for my lightbulb based on a W600 chip. By trial-and-error method, I managed to figure out five pins that are used for LED channels: red - pa5 green - pb13 blue - pb15 WW - pb8 CW - pb16 I can activate those via LED pin mode just fine,...

That W600 build has finally succeeded, it seems. It should be ready for testing.

Very well, it went easier than expected. Let me merge this branch and now let's look into the second issue. Still, I am suprised that the code below does not work: Code: C / C++Log in, to see the code Let's try to insert a conditional pwm_stop here (if value is 0): Again, wait for the build to finish and check, also watch for flickering when adjusting PWM value (I am not sure if this platform likes repeated start calls)

It seems that not yet all PWM pins are enabled in hal_pins_w800.c, which is also used for W600: Code: C / C++Log in, to see the code I can try to enable remaining pins for you, would you be able to test new build once it's ready? I don't have W600 at hand, so it might take several attempts to get it right.

Sure. Let's try it. I prefer using OTA, so I don't have to desolder the chip again.

Code: text Expand Select all Copy to clipboard red - pa5 green - pb13 blue - pb15 WW - pb8 CW - pb16 According to datasheet, PA5 is PWM_1, PB13 is PWM_2, PB15 is PWM_4, PCB8 is PWM_5 and PB16 is PWM_3 , so it should work. Can you download build files from this pull request (find download build artifacts, unpack zip), do OTA, and recheck?

As far as I see all Wxxx images are failed to build, therefore there are no images of them inside the artifacts zip. Can you check please?

Sorry, there must be some typo or something, I am helping now in about 4 threads and I am doing it in round robin manner, I haven't noticed it failing. Oh yes, it's a typo: I have put a dot instead of a comma. Let me fix this... and then try. Added after 1 [minutes]:When you test it, please test two things: - are the PWMs that worked before STILL working? - are new PWMs working? Please REBOOT between every try, just to be sure... later check without reboots. Again, I don't have this device, so I need your help with testing. Added after 9 [minutes]:EDIT: One more fix added

While it builds, I've noticed that PWM works a bit strangely. It never fully turns the channel off. Even on 0 or toggle off, it still glows slightly. Gonna check the new build now. Thank you for your time. I appreciate your help so much.

If you have time to test more, we can also fix this next issue as well. Maybe we need to turn off PWM entirely or smth.

Sure thing. As long as you have time. Added after 13 [minutes]:Tested all 5 PWM channels separately and they all work well. Except for the not turning off part. One more question, how should I properly number the channels?

Tested all 5 PWM channels separately and they all work well. Figured out the proper channel numbers too, so now I can set brightness, temperature, and color.Everything works, except for the not turning off part.

Tested the new build and now everything works as it should! Channels work exactly as they should and 0 PWM actually turns off the channel. Color channels do not interfere with each other either. Thank you so much for your work!

[W600 Chip] Configuring PWM for RGBCCT Lightbulb LED Channel Brightness Control

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#1 20884210 31 Dec 2023 00:12

DanteBC DanteBC

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Post #1
20884210 31 Dec 2023 00:12

Disassembled and successfully flashed an openbeken firmware for my lightbulb based on a W600 chip.

By trial-and-error method, I managed to figure out five pins that are used for LED channels:
red - pa5
green - pb13
blue - pb15
WW - pb8
CW - pb16

I can activate those via LED pin mode just fine, but I feel like I need a PWM mode to actually control channel brightness. But it looks like I can only enable PWM mode on pins pb14-18. Maybe I need to use some other pin mode I'm missing. As far as I understand, there is no LED controller in this lightbulb because channels are controlled directly. Can anyone help me with this?
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#2 20884432 31 Dec 2023 09:46

p.kaczmarek2 p.kaczmarek2

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Post #2
20884432 31 Dec 2023 09:46

It seems that not yet all PWM pins are enabled in hal_pins_w800.c, which is also used for W600:
Code: C / C++
Log in, to see the code

I can try to enable remaining pins for you, would you be able to test new build once it's ready? I don't have W600 at hand, so it might take several attempts to get it right.

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

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#3 20884444 31 Dec 2023 09:57

DanteBC DanteBC

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Post #3
20884444 31 Dec 2023 09:57

p.kaczmarek2 wrote:
I can try to enable remaining pins for you, would you be able to test new build once it's ready? I don't have W600 at hand, so it might take several attempts to get it right.

Sure. Let's try it. I prefer using OTA, so I don't have to desolder the chip again.
#4 20884639 31 Dec 2023 11:58

p.kaczmarek2 p.kaczmarek2

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Post #4
20884639 31 Dec 2023 11:58

Code: text Expand Select all Copy to clipboard
red - pa5 green - pb13 blue - pb15 WW - pb8 CW - pb16

According to datasheet, PA5 is PWM_1, PB13 is PWM_2, PB15 is PWM_4, PCB8 is PWM_5 and PB16 is PWM_3 , so it should work.
Can you download build files from this pull request (find "download build artifacts, unpack zip"), do OTA, and recheck?
https://github.com/openshwprojects/OpenBK7231T_App/pull/1015

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

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#5 20884691 31 Dec 2023 12:16

DanteBC DanteBC

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Post #5
20884691 31 Dec 2023 12:16

As far as I see all Wxxx images are failed to build, therefore there are no images of them inside the artifacts zip. Can you check please?
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#6 20884697 31 Dec 2023 12:28

p.kaczmarek2 p.kaczmarek2

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20884697 31 Dec 2023 12:28

Sorry, there must be some typo or something, I am helping now in about 4 threads and I am doing it in "round robin" manner, I haven't noticed it failing.
Oh yes, it's a typo:

I have put a dot instead of a comma. Let me fix this... and then try.

Added after 1 [minutes]:

When you test it, please test two things:
- are the PWMs that worked before STILL working?
- are new PWMs working?
Please REBOOT between every try, just to be sure... later check without reboots. Again, I don't have this device, so I need your help with testing.

Added after 9 [minutes]:

EDIT: One more fix added

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

Helpful post? Buy me a coffee.
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#7 20884731 31 Dec 2023 12:36

DanteBC DanteBC

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Post #7
20884731 31 Dec 2023 12:36

While it builds, I've noticed that PWM works a bit strangely. It never fully turns the channel off. Even on 0 or toggle off, it still glows slightly.

Gonna check the new build now. Thank you for your time. I appreciate your help so much.
#8 20884734 31 Dec 2023 12:37

p.kaczmarek2 p.kaczmarek2

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Post #8
20884734 31 Dec 2023 12:37

If you have time to test more, we can also fix this next issue as well. Maybe we need to turn off PWM entirely or smth.

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

Helpful post? Buy me a coffee.
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#9 20884736 31 Dec 2023 12:53

DanteBC DanteBC

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Post #9
20884736 31 Dec 2023 12:53

Sure thing. As long as you have time.

Added after 13 [minutes]:

Tested all 5 PWM channels separately and they all work well. Except for the not turning off part.
One more question, how should I properly number the channels?
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#10 20884764 31 Dec 2023 12:54

p.kaczmarek2 p.kaczmarek2

Moderator Smart Home

Helpful post? (+1)

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Post #10
20884764 31 Dec 2023 12:54

That W600 build has finally succeeded, it seems. It should be ready for testing.

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

Helpful post? Buy me a coffee.
#11 20884822 31 Dec 2023 13:19

DanteBC DanteBC

Level 4

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Post #11
20884822 31 Dec 2023 13:19

Tested all 5 PWM channels separately and they all work well.
Figured out the proper channel numbers too, so now I can set brightness, temperature, and color.
Everything works, except for the not turning off part.
Helpful post

#12 20884872 31 Dec 2023 13:38

p.kaczmarek2 p.kaczmarek2

Moderator Smart Home

Helpful post? (+1)

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Post #12
20884872 31 Dec 2023 13:38

Very well, it went easier than expected. Let me merge this branch and now let's look into the second issue.

Still, I am suprised that the code below does not work:
Code: C / C++
Log in, to see the code

Let's try to insert a conditional pwm_stop here (if value is 0):
https://github.com/openshwprojects/OpenBK7231T_App/pull/1016
Again, wait for the build to finish and check, also watch for flickering when adjusting PWM value (I am not sure if this platform likes repeated start calls)

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

Helpful post? Buy me a coffee.
#13 20884900 31 Dec 2023 13:54

DanteBC DanteBC

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Post #13
20884900 31 Dec 2023 13:54

Tested the new build and now everything works as it should! Channels work exactly as they should and 0 PWM actually turns off the channel. Color channels do not interfere with each other either. Thank you so much for your work!
#14 20884917 31 Dec 2023 14:02

p.kaczmarek2 p.kaczmarek2

Moderator Smart Home

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Post #14
20884917 31 Dec 2023 14:02

You're welcome, and now.. once you have this bulb fully working, can you tell me whether it's present on our list?
https://openbekeniot.github.io/webapp/devicesList.html
If not, consider posting a short teardown/guide (maybe some photos or marking from package, info where it was bought, etc...)

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

Helpful post? Buy me a coffee.
#15 20884951 31 Dec 2023 14:15

DanteBC DanteBC

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Post #15
20884951 31 Dec 2023 14:15

It's not present there. I'll make a few pictures of the insides, while it's in the disassembled state, and a few assembled too. I don't have the packaging as it was bought quite a while ago. But I'll provide as much info as I can.
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Topic summary

✨ The discussion revolves around configuring PWM for an RGBCCT lightbulb utilizing a W600 chip after flashing it with openbeken firmware. The user identified the pins for the LED channels and sought assistance in enabling PWM mode for brightness control. Responses indicated that not all PWM pins were enabled in the firmware, and a collaborative effort ensued to modify the code. After several iterations, the PWM channels were successfully tested, resolving issues with channel brightness control and ensuring that a PWM value of 0 effectively turned off the channels. The user also agreed to document the lightbulb for inclusion in a device list.
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FAQ

TL;DR: On a W600 RGBCCT bulb, 5 PWM channels now work; “All 5 PWM channels … work well.” Update firmware, map pins, and use the 0% off fix. [Elektroda, DanteBC, post #20884822]

Why it matters: This helps makers fix dimming and true-off behavior on W600-based RGBCCT bulbs using OpenBeken.

Quick Facts

Proven pin map for one W600 RGBCCT bulb: Red=PA5, Green=PB13, Blue=PB15, Warm=PB8, Cool=PB16. [Elektroda, DanteBC, post #20884210]
PWM channel mapping: PA5→PWM_1, PB13→PWM_2, PB16→PWM_3, PB15→PWM_4, PB8→PWM_5. [Elektroda, p.kaczmarek2, post #20884639]
OTA was used for builds, avoiding any desoldering during testing. [Elektroda, DanteBC, post #20884444]
0% PWM now fully turns off LEDs after the fix; no channel crosstalk observed. [Elektroda, DanteBC, post #20884900]
When testing new builds, reboot between tries to validate behavior. [Elektroda, p.kaczmarek2, post #20884697]

Which W600 pins drive RGBCCT channels on this bulb?

The tested bulb routes channels as follows: Red = PA5, Green = PB13, Blue = PB15, Warm White = PB8, Cool White = PB16. These pins were discovered by probing and then verified under OpenBeken after enabling PWM per pin. Use this as a starting map for your device. If your board differs, re-check with a meter and LED tests. [Elektroda, DanteBC, post #20884210]

How many PWM channels were verified working on W600 for this build?

Five PWM channels were tested individually and confirmed to work. After assigning the pins, the user could set brightness, color temperature, and color successfully. This verified end-to-end control across RGBCCT. If any channel fails, recheck its role and PWM assignment. [Elektroda, DanteBC, post #20884822]

Which W600 pins support PWM for brightness control?

According to the provided mapping, PA5 is PWM_1, PB13 is PWM_2, PB16 is PWM_3, PB15 is PWM_4, and PB8 is PWM_5. These channels enable smooth dimming when configured in OpenBeken. Assign the PWM role to each listed pin to control RGBCCT outputs. [Elektroda, p.kaczmarek2, post #20884639]

How do I enable PWM on W600 and map channels in OpenBeken?

Update to a build that enables W600 PWM pins, then perform OTA flashing.
In OpenBeken, assign each discovered pin the PWM role matching its PWM_x index.
Test each channel’s dimming and verify brightness, CT, and color control. This procedure validated RGBCCT control on the referenced bulb. [Elektroda, p.kaczmarek2, post #20884639]

Why do my LEDs glow faintly at 0% PWM, and how do I fix it?

Earlier firmware reduced duty to zero but left PWM running, causing faint glow. A fix added a conditional stop so 0% fully disables the PWM output. As the maintainer put it, “insert a conditional pwm_stop.” Update to a build containing this fix to eliminate residual glow. [Elektroda, p.kaczmarek2, post #20884872]

After the fix, does 0% PWM fully shut off the channel?

Yes. The tester confirmed that 0% PWM now truly turns off the LED channel. They also noted normal operation with independent channels, which indicates correct PWM stop behavior at zero. Update and re-test if you still see a faint glow. [Elektroda, DanteBC, post #20884900]

Do color channels interfere with each other during dimming?

No. After applying the fixed build, color channels operate independently without crosstalk. This allows reliable RGBCCT mixing and scene transitions. If you see coupling, check wiring or transistor leakage on your specific board. [Elektroda, DanteBC, post #20884900]

What is the correct PWM channel numbering to use?

Use the mapping from the maintainer: PA5→PWM_1, PB13→PWM_2, PB16→PWM_3, PB15→PWM_4, PB8→PWM_5. Assign these indices to your RGBCCT roles in OpenBeken. This aligns the firmware’s PWM channels with the W600 hardware. [Elektroda, p.kaczmarek2, post #20884639]

How can I update firmware without desoldering the W600 module?

Use OTA updates. OTA was preferred and used throughout testing, avoiding desoldering. Flash the provided OpenBeken test build over the network, then verify PWM behavior. Ensure stable power and Wi‑Fi during OTA to prevent interruptions. [Elektroda, DanteBC, post #20884444]

What should I verify after flashing a test build?

Confirm that PWM channels which previously worked still behave correctly. Then check that newly enabled PWM pins operate and dim as expected. Reboot between tries to ensure clean initialization before each test run. This helps isolate configuration issues from transient states. [Elektroda, p.kaczmarek2, post #20884697]

Can changing brightness cause flicker on W600?

It can under certain conditions. The maintainer advised to “watch for flickering when adjusting PWM value,” especially with repeated starts. The 0% stop fix reduces residual output but repeated start calls might still cause artifacts on this platform. Test carefully at low duty levels. [Elektroda, p.kaczmarek2, post #20884872]

What PWM duty/value range does OpenBeken use on W600?

OpenBeken uses a 0–100 value for brightness, then scales by 2.55 to set hardware duty (0–255). This conversion ensures full-range control while keeping a simple percentage in UI and scripts. Update logic applies the stop at 0% to fully disable output. [Elektroda, p.kaczmarek2, post #20884872]

How do I share my working bulb so others benefit?

Check if your device appears on the OpenBeken devices list. If not, post a short teardown or guide with photos and purchase details. This helps others identify compatible bulbs and replicate your configuration. [Elektroda, p.kaczmarek2, post #20884917]

What caused the initial build failure for W600 images?

A simple typo in the code caused the W600 images to fail. The maintainer noted placing a dot instead of a comma, then fixed it and rebuilt. After that, testing proceeded via OTA. [Elektroda, p.kaczmarek2, post #20884697]

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