Unknown LED driver: CB-2S BK7231N + BP2958, what is the middle IC?

Question

Hello everyone. I got an LED driver for an LED chandelier. The CB-2S module (BK7231N) is soldered on the board, an unknown microcircuit and analog drivers with PWM regulation BP2958. On the CB-2S, only 3.3 V, GND, TX1, RX1 are soldered. Pins TX1 and RX1 are connected to an unknown chip directly, and this chip is connected from BP2958 to PWM pins. Does anyone have an understanding of how it all works? There are plans to flash on OpenBK.

divadiow · Answer

this is a TuyaMCU device. CB2S talks to the MCU over rx/tx. The M3-DSR751-I01E controls the LEDs

Log in, to see the code

Added after 4 [minutes]:

assuming the device in this thread (PCB marked DS_LED02), is the same as the one with dump in here https://www.elektroda.com/rtvforum/topic4173909.html

Is the N is DNS_LED02 in title a typo?

Added after 44 [minutes]:

also, what's your device? A 2.4G DESE - something like this?

GreedyMagnetometer · Answer

>>21906532 Yes), N This is a typo, it looks like the device in your photo. The connection lines are clear to me, I'm trying to find out which signal goes from the CB-2S to the microcircuit. The chip itself is strange, has a radio channel, because this module can be controlled via a radio remote control.

p.kaczmarek2 · Answer

Interesting, so M3-DSR751-101E with the crystal oscillator and antenna is used as TuyaMCU chip? Well, the "signal" is probably TuyaMCU traffic over UART.
TuyaMCU protocol - communication between the microcontroller and the WiFi module
TuyaMCU analyzer - UART packet decoder for Tuya devices - dpID detector
TuyaMCU flashing, setup and configuration guide - configure dpIDs for Home Assistant

Added after 45 [seconds]:

@GreedyMagnetometer have you managed to investigate it futher?

GreedyMagnetometer · Answer

>>21909335 Unfortunately, I didn't get any further. The scheme of operation is as follows: microcircuit M3-DSR751. This is some kind of controller that controls the PWM drivers via radio control via a remote control, and the CB-2S module is an add-on to control it via WiFi, because there are versions of this LED driver without CB-2S.

p.kaczmarek2 · Answer

Ok but at which point are you stuck? 1. did you take factory backup 2 MB copy? 2. did you try capturing UART traffic (while powering it from safe power supply, not from mains)? 3. alternatively, did you try flashing OBK, and starting TuyaMCU driver to see if there are heartbeats seen, at either of common TuyaMCU bauds? That's classic TuyaMCU idea. That's how TuyaMCU devices are often made. The same devices are also sold without the WiFi module.

GreedyMagnetometer · Answer

>>21910400 I made a backup copy of the factory firmware. I have not tried to intercept traffic, because I have already flashed it. I can't figure out how to try to send commands for the Tuya MCU response.

divadiow · Answer

schema/dpIDs needed for TuyaMCU config on OBK are in the text box in post #2. Added after 51 [minutes]:try this basic autoexec.bat and reboot. Code: TextLog in, to see the code

p.kaczmarek2 · Answer

@divadiow do we know baud it uses? Let's double check from his 2 MB copy: Standard 9600, it seems

Unknown LED driver: CB-2S BK7231N + BP2958, what is the middle IC?

Post #1

Post #2

Post #3

Post #4

Post #5

Post #6

Post #7

Post #8

Post #9

Didn't find an answer? Ask Artificial Intelligence

Topic summary