FAQ
TL;DR: This FAQ maps 10 GPIO assignments for the 4-relay CB3S board, and an experienced contributor confirmed RF can be “independent.” It helps Tuya TYWB-4CH-RF/TYWD-4CH-RF owners flash BK7231N safely, reuse the board with ESPHome or OpenBeken, and understand why RF may still work after firmware changes. [#21144422]
Why it matters: This thread answers the practical blockers that stop these 4-channel garage or gate controllers from being flashed, mapped, and reused reliably.
| Variant |
Supply input |
Wi-Fi module |
RF behavior from thread |
Notes |
| TYWD-4CH-RF |
Low-voltage DC |
CB3S / BK7231N |
RF reported independent on some boards |
OpenBeken database name: TYWD 4CH-RF |
| TYWB-4CH-RF |
AC mains / 230 V version mentioned |
CB3S or WB3S |
Same relay/button GPIO layout reported |
Cloudcutter firmware worked on one WB3S case |
| 7-32V / 5V USB naked board |
7-32 V DC or 5 V USB |
CB3S / BK7231N |
RF still paired after OBK install |
Same basic hardware family |
Key insight: The most important finding is that the RF section is often handled by a separate chip, not by the CB3S itself. That is why RF can keep working after OpenBeken is installed, and why JSON fields like remote_io do not automatically give you usable RF control in custom firmware. [#21144422]
Quick Facts
- The exported Tuya config maps 4 relays, 4 channel buttons, 1 toggle-all button, and 1 Wi-Fi LED: relay pins P24, P6, P26, P14; button pins P8-P11; toggle-all on P7; Wi-Fi LED on P22. [#20860235]
- The original dump shows
rf_width set to 345, remote_io to 20, and remote_select reported as 1 in one config, while another device dump later showed remote_select as 0. [#21125280]
- The Tuya firmware boot log identifies BK7231N firmware
1.3.10, Tuya IoT SDK 2.3.3, and build date 2022-12-07 15:29:01 for a matching board family. [#21144422]
- One flashing method used in-place wiring with RX, TX, and GND plus board USB power, then a power reconnect to enter the boot path; no CEN line was required in that recommended sequence. [#21120964]
How do I set up RF on this Tuya 4-channel garage door controller using the exported JSON config with fields like remote_io, remote_select, and rf_width?
You usually do not set up RF from that JSON alone. The thread later confirmed the RF section can operate independently, and one matching board kept pairing with a 3-button RF remote after OpenBeken was installed. The boot log from that board also printed
remote rf433 not enable, which shows the Tuya JSON fields were not enough to enable usable RF in custom firmware by themselves. In practice, first identify whether the RF receiver is on a separate chip or directly wired to the Wi-Fi module.
[#21144422]
What are the correct GPIO pin mappings for the Tuya Smart Life Garage Door Motor Receiver 4CH Switch Controller with a CB3S/BK7231N module?
The mapped pins are P24 relay 1, P6 relay 2, P26 relay 3, P14 relay 4, P8 button 1, P9 button 2, P10 button 3, P11 button 4, P7 toggle-all, and P22 Wi-Fi LED. The same post also states the module is CB3S, which uses BK7231N. That gives you 10 usable assignments before any RF work.
[#20860235]
What's the step-by-step process to flash a CB3S module in place with BK7231GUIFlashTool without desoldering it from the board?
Use the in-place serial method with a timed power reset. 1. Connect RX to TX, TX to RX, and GND to GND, then power the board from its USB input. 2. Start a flash read or flash operation in BK7231GUIFlashTool. 3. Disconnect 5 V and reconnect it to reset the board into the expected boot state. The contributor said this sequence should start flashing without removing the CB3S module.
[#21120964]
Why would someone desolder the CB3S and replace it for ESPHome instead of doing in-place flashing on the original BK7231N board?
They may desolder because they want native ESPHome on a different module, not just a reflashed BK7231N. The first post says the CB3S was removed from the board, then ESPHome was installed and the board was reused with explicit GPIO definitions for four gate actions. That approach also bypasses any board-level serial access problem that can block in-place flashing.
[#20860235]
Which pins should be connected to an FTDI adapter when flashing this BK7231N CB3S garage door board, and how should the power-cycle reset be done?
Connect FTDI RX to board TX, FTDI TX to board RX, and GND to GND. Then power the board separately through its USB port with 5 V, start the flash read, and briefly disconnect and reconnect that 5 V power. The same contributor explicitly said CEN was not needed in his preferred method.
[#21120964]
Why does BK7231GUIFlashTool or ltchiptool fail to connect to a CB3S board even when RX, TX, and GND seem to be wired correctly?
Connection often fails because the board never enters the right boot state or because RX/TX are loaded by other circuitry. The thread narrowed the main question to whether the serial lines were connected anywhere else on the PCB. When the normal 3.3 V reset method fails, the suggested fallback was a short CEN-to-GND pulse of about 0.25 s.
[#21122594]
How can I check with a multimeter whether the RX and TX lines on this Tuya CB3S board are connected to anything else that could block flashing?
Use continuity mode with all power removed. 1. Unplug the FTDI and all board power. 2. Set the meter to continuity mode and confirm it beeps when probes touch. 3. Put one probe on RX, then probe nearby pads, vias, and traces for a beep; repeat for TX. A beep means that line reaches another point that could interfere with flashing.
[#21121370]
What is a CB3S module, and how does it relate to the BK7231N chip in Tuya relay boards?
“CB3S” is a Tuya Wi-Fi module that carries the BK7231N system chip, providing wireless control and GPIOs for relay boards. In this thread, the extracted configuration and template both identify the board as CB3S-based, and the description states directly that CB3S uses BK7231N. That is why BK7231 flashing tools apply to this hardware family.
[#20860235]
What is the SYN590R RF receiver chip, and how is it used in TYWB-4CH-RF or TYWD-4CH-RF relay controllers?
“SYN590R” is a 433 MHz RF receiver IC that accepts remote-control signals and passes decoded events into the relay controller path, often as a separate hardware block. In this thread family, a contributor identified TYWB-4CH-RF and TYWD-4CH-RF as sharing the same Beken CB3S, the same RF SYN590, and the same relay and button GPIO layout.
[#21448020]
How do I configure this 4-channel relay board in ESPHome using the reported pins for relays, buttons, toggle-all, and WiFi LED?
Map four GPIO switches for relays and five GPIO binary sensors for buttons. The shared ESPHome example used P24, P6, P26, and P14 for relays; P8, P9, P10, and P11 for per-channel buttons; P7 for toggle-all; and P22 as an inverted status LED. The sample names were Open Gate, Close Gate, Stop Gate, and Gate SbS.
[#20860235]
When RF still works after installing OpenBeken, how can I tell whether the RF receiver is handled independently by another chip instead of by the CB3S firmware?
If RF still pairs and triggers after OpenBeken replaces the original firmware, the RF path is likely independent. One contributor reported exactly that on the 7-32 V or 5 V USB version: OpenBeken was running, yet a 3-button RF switch still paired and worked. Another contributor had already explained that an RF receiver integrated into another SOIC controller would need no OBK-side driver.
[#21144422]
TYWB-4CH-RF vs TYWD-4CH-RF: what are the real differences besides AC mains versus low-voltage DC power input?
The thread says the main practical difference is the input power section. A later post states TYWB-4CH-RF and TYWD-4CH-RF use the same Beken CB3S, the same RF SYN590, the same four relays and buttons, and the same GPIO usage. That means firmware mapping and RF hardware assumptions transfer across both names much more than the power-input label suggests.
[#21448020]
Where can I find the OpenBeken device template or database entry for this board, and what device name was used for it?
You can find it in the OpenBeken webapp device database entry added from this thread. The contributor posted the commit that added the board and said the model name used there was
TYWD 4CH-RF. He also pointed readers to the webapp device list where it would appear after publication.
[#21140406]
How do the 230V AC version and the 7-32V or 5V USB version of this Tuya 4-channel RF relay compare in GPIO layout, RF hardware, and firmware settings?
They appear very close in control hardware, despite different power inputs. The 230 V version shared a JSON with relays on P24, P6, P26, and P14, buttons on P8-P11, Wi-Fi LED on P22, and RF fields such as
remote_io:20 and
rf_width:345. The 7-32 V or 5 V USB board was reported to keep independent RF working after OpenBeken, which supports the same-hardware-family view.
[#21757257]
What should I do if the RF keychain pairs successfully on a WB3S version of the board but the relay never triggers afterward?
Try known-working firmware for that exact board family before changing hardware. In the thread, a WB3S owner with the same symptom reported success after flashing the
Tuya Generic TYWB-4CH-RF 4 Channel Relay firmware package, and then confirmed the
M button switched three relay operating modes. That is the clearest fix reported for the pair-without-trigger case.
[#21896563]
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