How to use PCA10040 as Dongle Scanner

[Sebastien Monat]

Hi,

I'm trying to have a PCA10040 working as a scanner of BLE peripherals to be able to connect to my own BLE Nordic device, write a characteristic and close the connection. To do that I followed those steps:

1. Flash `nRF5_SDK_14.1.0_1dda907/examples/ble_central/ble_app_uart_c on the PCA (Firmware + Soft device => make flash + make flash_softdevice)

2. sudo pip install pygatt

3. Clone the repo pc-ble-driver-py and type the command python2.7 heart_rate_collector.py NRF52 /dev/ttyACM0

This leads to an error : pc_ble_driver_py.exceptions.NordicSemiException: Failed to open. Error code: 13 I precise that I changed l627 in main.c of ble_app_uart_c the baud_rate to UART_BAUDRATE_BAUDRATE_Baud1M and I changed the python script on function main to baud_rate=1000000

After that I decided to erase all on PCA10040 and used your application nrfconnect-2.2.1. So this application Bluetooth Low Energy reflashed the PCA10040 with a firmware and a SoftDevice. This application is working fine and scan my own device and its custom char and service. I'm able to write on this custom char without any problem.

After that I'm able to connect to the PCA with heart_rate_collector.py with all the self.adapter.enable_notification commented. The self.adapter.service_discovery(new_conn) seems to work. My custom service and charateristics have an UUID of 0x00 when I add some debug on service_discovery function (I do not know if it is normal ?).

So at the end when I try to call self.adapter.write_cmd after adding the CUSTOM SERVICE UUID and CHAR UUID as you explained on this post I still have the error pc_ble_driver_py.exceptions.NordicSemiException: Characteristic value handler not found

So my question is : where can I find a simple python script or a simple C program doing scan-discovery-connect-write_char-disconnect ? The same thing your nrfconnect-2.2.1 is doing but with a script.

Thanks for your response. Regards

[Sebastien Monat]

Hi Jorgen !!!

Thank you for this pretty cool answer. I tried your script after flashing my PCA10040 with example/ble_central_ble_app_uart_c on SDK 14.1.0 without any changement. I used the command

$ python2.7 nus_collector.py NRF52 /dev/ttyACM0 

An this is the log :

Serial port used: /dev/ttyACM0
Traceback (most recent call last):
  File "nus_collector.py", line 196, in <module>
    main(serial_port)
  File "nus_collector.py", line 158, in main
    collector.open()
  File "nus_collector.py", line 73, in open
    self.adapter.driver.open()
  File "/usr/local/lib/python2.7/dist-packages/pc_ble_driver_py/ble_driver.py", line 126, in 
wrapper
    raise NordicSemiException('Failed to {}. Error code: {}'.format(wrapped.__name__, err_code))
pc_ble_driver_py.exceptions.NordicSemiException: Failed to open. Error code: 13

So I still have the problem. Do you have any idea ?

[Jørgen Holmefjord]

Did you flash the connectivity firmware manually? If you have the firmware flashed, but it is using the wrong baudrate, you might get this error. Please try erasing the board using nrfjprog -f nrf52 -e command and let pc-ble-driver-py do the firmware flashing for you. You can also try disabling the MSD when using Linux, some users have experienced similar issues when this is enabled.

[Jørgen Holmefjord]

Do you have nrfjprog installed? You also need J-Link drivers, as described in the section about required drivers and tools.

[Sebastien Monat]

Yes I have all the tools on my computer. I think I have to put nrfjprog on a special folder but I do not know which folder. Maybe /usr ?

[Jørgen Holmefjord]

Do you have the path to nrfjprog binary in your PATH environment variable? Which OS are you using?

[Sebastien Monat]

OK Jorgen I have put a PATH=$PATH:<MyFolderLocation> and it is working now. I'm able to see all the BLE peripherals on the range. Many thanks.

[robertsehlstedt]

Hello Jörgen!

I have a similar issue to this, but my error message looks something like this:

robban@:pca20020_s132$ python2.7 nus_collector.py NRF52
	0 : /dev/ttyACM0: 000682995637
 
Enter your choice: 0
Serial port used: /dev/ttyACM0
Traceback (most recent call last):
  File "nus_collector.py", line 196, in <module>
    main(serial_port)
  File "nus_collector.py", line 158, in main
    collector.open()
  File "nus_collector.py", line 73, in open
    self.adapter.driver.open()
  File "/usr/local/lib/python2.7/dist-packages/pc_ble_driver_py/ble_driver.py", line 99, in wrapper
    error_code=err_code,
pc_ble_driver_py.exceptions.NordicSemiException: Failed to open. Error code: 13

I have tried using the nrfjprog -f nrf52 -e command you recommended above, and my PATH includes the nrfjprog binaries. However I still cannot make it work, and the links to the wrong baudrate and similar issues above seem to be broken?

Also I have tried figuring out where the script actually determines which HEX-files should be written with the nrfconnect to my device, I can't seem to find it.

Would appreciate some help!

[Jørgen Holmefjord]

Are you using the correct version of pc-ble-driver-py? I would recommend that you post a new case where you describe your setup and environment in detail. That way we can help you debug the issue, without spamming this post.