[BC660K-GL] Is the VIO_SEL - GND connection essential for 3.3 V operation?

brixton · January 19, 2023, 3:53pm

Hello all

I have a MCU which runs at 3.3 V, and have interfaced that with a BC660K-GL through the main UART port. Due to prototyping reasons the VIO_SEL pin was unfortunately not connected to GND as was specified in the design guide (it’s at the bottom of the chip, therefore difficult to solder). Also, the 1 kOhm resistors were left out as well.

Now the problem is that my main MCU is not able to communicate with the BC660K, even though all the other connections are as they should be (as far as I can tell). So the question is, could the reason for the problem be that VIO_SEL is not connected to GND (or the missing resistors)? Or should it be able to function nonetheless?

Any feedback is much appreciated!

N.B. With the BC66 I managed to interface it to a 3.3 MCU with the main UART port, without any level conversion and then went fine (even though the hardware design guide advises to use level conversion). So I was hoping that for the BC660K-GL the same applies.

brixton · January 23, 2023, 4:45pm

@herbert.pan-Q , any ideas?

herbert.pan-Q · January 28, 2023, 2:51am

I think we can check by the following methods
1、First, just test whether main_tx/rx of the module is communicating properly
2、Determines whether the baud rates of the mcu match

brixton · February 13, 2023, 2:00pm

Thank you. I tried that, but there was no response from the BC660.

girishgbh · December 12, 2024, 3:37pm

Is this issue resolved?

We are also facing the same problem. In our prototype BC660K chip set is interfaced with MCU and VIO_SEL signal is floating. BC660K chip is not responding to any AT commands sent through the main UART. No sign of chip set alive.

Is there any way to fix this situation?
How to identify if the chipset is powered up and ready to respond to AT cmds?

Any pointers to resolve this issue will much appreciated.
Thanks.

herbert.pan-Q · December 13, 2024, 1:26am

pls note
1.The BC660K will turn on automatically when powered on, but you need to insert a SIM card or connect a SIM card
2.You can also supply 3.3V to the VBAT pin of the BC660K to try,If the BC660K starts up properly, the VDD_EXT will output 1.8V

girishgbh · December 13, 2024, 6:03am

Do we need SIM to be inserted for getting response to basic AT command?
Basically we are not getting any response from the BC660K chip for even “AT\r\n” cmd.

What about VIO_SEL signal? If is ok if this is floating or it must be connected to ground to get the chip working?

We are not able to make any progress, need support on resolving this issue.

girishgbh · December 13, 2024, 1:44pm

BC660K-GL module is not communicating with UART and also there is no voltage coming on VDD_EXT pin.

I have attached the schematics of our hardware design. Is there anything we are missing in our design?

herbert.pan-Q · December 17, 2024, 1:24am

If you are a corporate user of QUECTEL, I suggest you solve your problem through JIRA