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Bluefruit LE UART won't respond to AT commands
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Bluefruit LE UART won't respond to AT commands

by DrJohnW on Fri Jul 10, 2020 4:36 pm

I have a very simple circuit using the Adafruit Bluetooth LE UART Friend product ID 2479, and I am using it as a wireless interface between my amateur radio and software that controls the radio's functions. Pins 3 and 4 of the LE UART Friend are connected to pins 10 (TIN1) and 9 (ROUT1) of a MAX3323EEPE chip. I am using a 9V battery to power the unit. Software Revision is 0.8.1-Apr 10 2019 and firmware revision is S110 8.0.0,0.2, hardware revision 0x00D6.

Using the Bluefruit LE Connect App (iOS), the LE UART Friend appears and connects to the App easily, and it offered to upgrade the software to the latest version. I can change firmware versions easily. However, the LE UART Friend does not respond in any to any AT commands. I can see that information was sent, but no packets seem to be received.

I have sent AT commands with the switch set to CMD as well as to UART with no positive results. I have also tried a factory reset as described on the tutorial pages and it still won't respond to AT commands. Any suggestions would be greatly appreciated!

DrJohnW
 
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Re: Bluefruit LE UART won't respond to AT commands

by DrJohnW on Mon Jul 20, 2020 8:07 pm

Following up on my question and hoping for some kind of response. I am not sure if I toasted my Bluefruit chip somehow, or if there are some troubleshooting steps I can do. I’m not sure if I need to order another chip and start over or just give up on this project. Many thanks in advance for any help someone can offer!

DrJohnW
 
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Re: Bluefruit LE UART won't respond to AT commands

by Whetstone on Mon Aug 10, 2020 5:54 am

Hello,

Did you have any luck getting this to work. I am trying the same circuit to connect to a telescope R232 port. I have wired up the circuit and can connect the android app to the Bluefruit UART but not got further than that. I am now trying to work out how to get it to communicate to my telescope.

Whetstone
 
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Re: Bluefruit LE UART won't respond to AT commands

by chniyeba on Wed Aug 12, 2020 4:09 am

Any update on this? I'm encountering a same issue not sure there's some settings that need to be adjusted.

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Re: Bluefruit LE UART won't respond to AT commands

by Whetstone on Wed Aug 12, 2020 11:43 am

Not yet, it is not clear if i need to upload a sketch directly to the Bluefruit LE Uart friend to make it work as a wireless serial device.

Whetstone
 
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Re: Bluefruit LE UART won't respond to AT commands

by DrJohnW on Wed Aug 12, 2020 2:39 pm

I still have not received any replies or suggestions, unfortunately.

DrJohnW
 
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Re: Bluefruit LE UART won't respond to AT commands

by Whetstone on Wed Aug 12, 2020 3:40 pm

I found this method with raspberry pi for WiFi with a USB R232 prolific cable from the pi to the Telescope handset serial port. I have not tested it exhaustively but i have been able to drive the telescope from my android device over WiFi in initial tests just now.

https://hackaday.io/project/162681/instructions

Whetstone
 
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Re: Bluefruit LE UART won't respond to AT commands

by chniyeba on Wed Aug 12, 2020 4:18 pm

Oh wow that's a good sign hope it can be achieve, will be trying that this week wish me luck :)

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Re: Bluefruit LE UART won't respond to AT commands

by Whetstone on Wed Aug 12, 2020 6:06 pm

Also looking at the Bluefruit UART documentation it seems it does not respond to AT commands over bluetooth (which sort of makes sense for security). I will get get hold of a USB to TTL cable and try that next.

Whetstone
 
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Re: Bluefruit LE UART won't respond to AT commands

by Whetstone on Sat Aug 15, 2020 5:21 am

Hi,
I can confirm the bluefruit UART does not respond to AT commands when connected by bluetooth. You must connect by a USB to 3.3v TTL cable and you also need to tie the CTS pin to ground. I have been able to connect and send messages between my computer (cable) and android device (bluetooth) and send AT commands from my computer.
Also watch out you use the correct version of the firmware when updating BLEFRIEND32 (uart) not BLEFRIEND (SPI), I made this error at first.

https://learn.adafruit.com/introducing- ... e-recovery

I tried a R232 serial cable connection from the bluefruit device to the R232 serial port on my telescope via a MAX232 chip. Currently I cannot get my android device to connect by bluetooth and control my telescope. I will update if I can get this working. the telescope R232 parameters are RS-232C, 9600bps, No parity check, 8 data bits, 1 start bit, 1 stop bit.
I can only get my android to connect to the bluefruit by forgetting the device then pairing it again. The bluefruit baud rate is set to 9600 but do not know about the other parameters.

Whetstone
 
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Re: Bluefruit LE UART won't respond to AT commands

by adafruit_support_carter on Mon Aug 17, 2020 12:27 pm

@DrJohnW Sorry for the delayed response on this. Is the radio the only hardware you have available? For testing purposes, it would help to have something like an Arduino so we could fall back to checking things per the guide:
https://learn.adafruit.com/introducing- ... troduction

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Re: Bluefruit LE UART won't respond to AT commands

by DrJohnW on Tue Aug 18, 2020 10:11 am

@adafruit_support_carter Thank you for the reply! Yes, the radio is really the only hardware I have available, as I do not have an Arduino. I hooked up the output to an oscilloscope, and I can see output, but the waveform does not look very clean. I just find it odd that I can connect to the device, but it won't respond to AT commands, and it does not echo them either. Initially, I was seeing some echo of the commands, inconsistently, but I had a bad TTL chip. When I replaced it with one I know to be good, I lost the echo capability.

DrJohnW
 
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Re: Bluefruit LE UART won't respond to AT commands

by adafruit_support_carter on Tue Aug 18, 2020 10:28 am

Unfortunately, hard to say then. With the unknown hardware (radio) and the TTL/RS232 translating going on, it could be multiple things. It sounds like you got it at least partially working at some point though.

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Re: Bluefruit LE UART won't respond to AT commands

by Whetstone on Sun Aug 23, 2020 12:32 pm

I got this to work with a bluetooth 2.1 module that supports SPP bluetooth profile. Only problem is it will not connect to android device on second use so need to forget and re pair the bluetooth module in android setting each time I use it.

Whetstone
 
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Please be positive and constructive with your questions and comments.