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Published 20 hours ago • verified publisher icon openshwprojects

CB2S cannot flash, "Cannot get bus."

Open Suxsem opened this issue 3 years ago • 7 comments
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Hello guys, I'm trying to flash OpenBK7231N_QIO_1.12.0.bin on my CB2S

I'm using a ft232rl USB<-> TTL adapter. I have connected: RX -> TX TX -> RX GND -> GND

I didn't soldered the Vcc pin because I'm powering the module from the mains voltage (I'm using un unplugged notebook to avoid current loops).

So these are my steps:

  1. python uartprogram OpenBK7231N_QIO_1.12.0.bin --unprotect -d com6 -w --startaddr 0x0
  2. As soon as I get the "programm...." I connect the module to the mains voltage I see the led blinking but I always get "Cannot get bus.". Can you help me please?

Thank you!

Suxsem avatar Jul 26 '22 08:07 Suxsem

Look for a pin labeled CEN. https://developer.tuya.com/en/docs/iot/cb2s-module-datasheet?id=Kafgfsa2aaypq

Solder a wire to it, and leave it floating and once you have the module powered, briefly jump it to ground. No need to hold it there. Data should then start flowing.

death2all110 avatar Jul 26 '22 14:07 death2all110

@death2all110 tried with no luck... I also tried to power the module with the UART adapter 3.3v without any luck... i'm stuck

Suxsem avatar Jul 26 '22 14:07 Suxsem

Which device is this? Also, just to confirm, you are soldered to TX1 and RX1 correct? TX2 and RX2 will not work, those are just for logging output.

death2all110 avatar Jul 26 '22 15:07 death2all110

@death2all110 moes MS-150B (dual channel dimmer). Yes TX1 and RX1

Suxsem avatar Jul 26 '22 15:07 Suxsem

I still WOULD NOT try to mess with mains, it's very dangerous!

Maybe it's a TuyaMCU device?

openshwprojects avatar Jul 26 '22 17:07 openshwprojects

IF it's TuyaMCU it uses TX1 and RX1 to communicate with TuyaMCU, so you need to unsolder these two pins before flashing. Other options that I had success with sometimes is to just unsolder vcc 3v from bekken board, then power it from there, that way tuyaMcu doesnt get powered and it doesn't interfere with tx/rx1. But best bet is to unsolder both Rx1 and Tx1 it worked for me 10/10

Stef-90 avatar Jul 26 '22 20:07 Stef-90

my device had rx soldered to a switch. there was a little external pulldown resistor soldered to the cb2s module. i couldn't flash as long as the mentioned resistor was in place. maybe your board is wired up in a similar way.

l3ztum avatar Jul 28 '22 18:07 l3ztum

Yes, you should check for capacitors and pull down resistors, and for TuyaMCU on TX/RX lines. If present, temporarily, remove.

openshwprojects avatar Nov 04 '22 07:11 openshwprojects