about nRF52-ble-long-range-demo

[Dai.Ima]

Hi,

I'm trying to measure the communication distance with Coded PHY using two nRF52840s and the demo software below,

but there are some problems. They are shown below.

https://github.com/NordicPlayground/nRF52-ble-long-range-demo

a. Buttons and LED configurations are described in nRF52-ble-long-range-demo/readme.md, but LED doesn't light up after writing the specified hex file.

　Are there other settings?

b. I understand that I need a Serial Port Viewer (for example Tera Term or Realterm) to see RSSI,　but is there anything else I should do? For example, program modifications,

   and When using the Serial Port Viewer, is it necessary to supply power to the board with a battery or the like?

c. When the writing of the software is completed, the power of the board is turned off, and it is restarted, the software disappears. Is this due to lack of memory?

It's my first time working with a board like this, so sorry for the elementary questions.

Best Regards,

[ovrebekk]

Hi

c. When the writing of the software is completed, the power of the board is turned off, and it is restarted, the software disappears. Is this due to lack of memory?

This shouldn't happen, no. The firmware is stored in flash memory, which will be retained during power down. 

If you press the reset button on the board after it wakes up will the code start running then?

Did you remember to reconnect the RTT viewer application after powering up the board?

Best regards
Torbjørn

[Dai.Ima]

Hi,

Thank you for your reply.

 I checked the board, the firmware was stored in flash memory.

I think I misunderstood that the firmware update method was wrong and the LED didn't light up,

so the firmware wasn't saved.

Best regards

[ovrebekk]

Hi

Does that mean you now got everything working, or do you still have some issues getting the demo to run?

Best regards
Torbjørn

[Dai.Ima]

Hi,

I got everything working.

But I have a question. RSSI display in Central. Is this Central's RSSI or Peripheral's RSSI?

As next step, I added FEM between A and nRF82540 on Central side, but RSSI didn't change with or without FEM. I want to determine whether it is due to the operation of FEM.

Best Regards,

[ovrebekk]

Hi 

The RSSI displayed on the central side should be the signal strength of the incoming signal from the peripheral. 

In other words if you add a FEM on the central side it needs to have an LNA (rather than a PA) to boost the RSSI seen on the central side. 

Best regards
Torbjørn

[Dai.Ima]

Hi

Thank you for your support.

I understand  the RSSI displayed on the central side and it needs to have an LNA  to boost the RSSI seen on the central side. 

When I use LNA or FEM, I know that I need a signal to control the LNA. Does the nRF52840-DK have ports for extracting control signals like TXEN(Tx enable) and RXEN(Rx enable)? If it doesn't exist, do we have to modify it ourselves?

Best Regards,

[ovrebekk]

Hi

Many of the Bluetooth SoftDevices support automatic control of TX enable and RX enable pins for use with PA/LNA solutions, yes. 

You can enable these signals on any pins you like, by using the sd_ble_opt_set(..) function, and all the GPIO pins are available on pin headers on the nRF52840DK. 

Just make sure to select pins that aren't already used for something else, such as buttons or LED's. 

Best regards
Torbjørn 

[Dai.Ima]

Hi

Thank you for your reply.

I have a question.

To enable the sd_ble_opt_set(..) function, What part of the firmware should I change? Also, in order to enable the sd_ble_opt_set(..) function, are there any other preparations other than the app and firmware you provide?

Best Regards

Dai.Ima

[ovrebekk]

Hi

Essentially you should call this function after you have enabled the SoftDevice, before you start any BLE activity (like advertising). It would make sense to include it as a part of the GAP initialization phase. 

If you have a look at this old blog, it includes an example function showing how you can use this function to enable external PA/LNA. 

Best regards
Torbjørn

[Dai.Ima]

Hi

Thank you for your reply.

I read the blog you introduced. In the blog, the case of S132 was described. I understand that it is the same when applied to others (for example, S140), is that correct?

Best Regards

Dai.Ima

[ovrebekk]

Hi 

Yes, this should be the same on the S140, as long as you use the same version number or newer. Older versions of the SoftDevices did not have support for controlling PA/LNA devices. 

Best regards
Torbjørn