Discovery: Tuya PCI-Express PC Switch/Reset Card -TuyaMCU [CBU] [STC8H1K08]

Bought this little thing from Ali Express. It's tiny. It's a PCI-Express x1 slot smart remote IoT power on/off/reset device for your PC. This is the cheaper one with no header bracket or external aerials. Some appear to come with what looks like a WB3S/CB3S but this one is with CBU module and an STC8H1K08 TuyaMCU. It arrived in an anti-static bag without box or instructions. It comes with 2 sets of 4 header pins for connecting to your motherboard.



Boot from CBU TX2



Quite a recent dated SDK used

< TuyaOS V:3.8.18 BS:40.00_PT:2.3_LAN:3.5_CAD:1.0.5_CD:1.0.0 >< BUILD AT:2024_07_09_13_40_54 BY ci_manage FOR tuyaos-iot AT bk7231n >

Tuya appear to have changed their way of pairing, no uuid/authkey/pskkey in the firmware.








This is what I have traced so far.



and I can see the communications between the CBU and MCU are being deciphered successfully by TuyaMCU Analyser at 9600 baud.

I'll update the post with more info as I find it. I'm not sure what I will/can use this device for. Posting what I have for now as I have a habit of losing posts!

Regarding the physical setup, the device only caters for 1 reset switch and 1 power switch. The card headers are intended to be connected to logically sit in between the PC motherboard headers and the chassis reset and power buttons. Translations of the text on the PCB make this clearer.



Added after 1 [hours] 3 [minutes]:

Paired with the Tuya app and from power-up, TuyaMCU Analyser displays the following. No commands sent to device from the app at this stage. It should be noted that no switch or motherboard connections are in place so the Tuya app reports the PC to be OFF through these actions.

---

Pressing the "PC Status" power button in the app gives

---

Pressing "Reset" -> "RESET"

---

Pressing "Reset" -> "Force Reset" gives


so this appears to be the extent of dpIDs and values


But I should probably next look to simulate PC status by jumpering headers or something. I'll need a way to test effect of commands on header pins on the device and the comms from MCU to CBU if the PC state is powered-on.

Added after 2 [hours] 11 [minutes]:

just noticed this similar device's MCU also sends "na90jncjlvw5t0ba" to the wifi module

Hello, I have the same device and was wondering if you have figured out the settings for the TuyaMCU to work with OpenBeken.

Hi no, I never completed it in the end after I shorted something on the TuyaMCU and it all died.