Please tell me how to connect one nRF51822 and another as Central and Peripheral. In the future, I would like to connect one Central and multiple Peripheral.

[tadanohito]

I am new to BLE.

My question is similar to the one below.

https://devzone.nordicsemi.com/f/nordic-q-a/22596/nrf51822-central-connect-and-communicate-with-2-peripherals

But the link to the answer was broken and I couldn't find it, so I'll ask.

I am using two nRF51822 and SDK12.3.0. I want to run them as Central on one side and Peripheral on the other. 

Probably by a method called GATT communication.(It means communication in a connected state.)

My goal is to record  RSSI and receiving time in Central when it receives an empty packet from Peripheral.

I would like to receive packets at intervals of 1msec to 10msec,

so advertising with long transmission intervals and randomly staggered transmission times would not achieve my goal.

In the future, I would like to receive packets from about 6 peripherals and record the RSSI of the packets.

Please let me know if there is a sample program or code that fits my purpose.

I'm not very good at English, so I use translation software to create my texts. I'm sorry if I don't make sense in some parts.

[awneil]

Note that nRF51 are not recommended for new BLE designs:

https://devzone.nordicsemi.com/f/nordic-q-a/13244/is-nrf52-recommended-over-nrf51-for-new-development/187456#187456 - and that was over 2 years ago.

tadanohito said:

the link to the answer was broken and I couldn't find it

That's always going to be a problem with going so far back.

Have you considered using nRF52 instead - so that you'll have up-to-date support ... ?

[tadanohito]

I understand that the nRF52 is better than the nRF51. Is it possible to achieve my goal with nRF52?

If multiple networks are difficult, what about 1:1 networks?

[tadanohito]

Is it a set like this?

awneil said:

Have you got the RTT configured to go over UART or RTT ?

I'm sorry, I don't understand well what you mean.

I also checked "NRF_LOG_BACKEND_SERIAL_USES_RTT".

https://devzone.nordicsemi.com/nordic/nordic-blog/b/blog/posts/debugging-with-real-time-terminal

awneil said:

TeraTerm won't see RTT ...

Does that mean I should check LOG? with other software or keil?

[awneil]

This bit says you have both RTT and UART enabled:

Sigurd - not sure if that's allowed?

[tadanohito]

I see.

I tried checking one side at a time, but it didn't work.

[tadanohito]

Am I using "ble_app_multilink" incorrectly?

I am using an evaluation board called EBSGCNZWY made by TAIYOYUDEN.

I'm using an evaluation board called EBSGCNZWY made by TAIYOYUDEN, and the number of LEDs is smaller than the sample expects.

I don't want to light up the LEDs, I just want to get the RSSI when connected to a specific "Peripheral".

Maybe I'm using the wrong code as a reference?

[awneil]

tadanohito said:

Maybe I'm using the wrong code as a reference?

Obviously, the Nordic examples are written to run directly on the Nordic Dev Boards.

That's why it's always best to start on the manufacturer's own board in order to get familiar with the product, the SDK, the tools etc - this applies to any manufacturer, not just Nordic.

Once you have gained sufficient experience on the manufacturer's board, then you will be in a position to move on to custom and/or 3rd-party boards.

So I would strongly suggest that you get this working first on Nordic Dev Kits ...

[tadanohito]

I see.

But this time I can't change the board.

But this time I can't change the board, because my mission is to use this board to get RSSI, and I have a limited amount of time available for that.

Is there anything wrong with my code in connecting with "ble_app_hrs" to get the RSSI?

1134.sdkroot.zip

I use "ble_app_multilink_central" and "ble_app_hrs".

[Sigurd]

tadanohito said:

But this time I can't change the board.

Looking at https://no.mouser.com/datasheet/2/396/TY_BLE_CN_EVBManual_V1_5_20180530-1324564.pdf the UART pins used, does not match the pins we use on the DK.

EBSGCNZWY board:

So in sdk_config.h, change the nrf_log uart pins to match your board,

for the DK, the configurations looks like this:

You need to use pin 0,1,2,3 instead.

----

If this board don't have LF crystal, you also need to configure the SoftDevice to use the internal RC oscillator instead.

Snippet:

static void ble_stack_init(void)
{
    ret_code_t err_code;

  
	
	    nrf_clock_lf_cfg_t clock_lf_cfg = { .source  = NRF_CLOCK_LF_SRC_RC,
                                        .rc_ctiv = 4,
                                        .rc_temp_ctiv = 1 };

Also, note this from page 8 in the module user guide:

[tadanohito]

Thank you for your advice.

But I failed.

"COM3" is central, "COM4" is peripheral.

Sigurd said:

Also, note this from page 8 in the module user guide:

I have fixed it in "system_nrf51.c" in the first setup when I bought it.

[tadanohito]

I was able to run the central "ble_app_uart.c" which is not "ble_app_multilink" and the peripheral programs.

I was able to confirm the reception of advertisement packets from peripheral.

However, I haven't been able to establish the connection between central and peripheral and check RSSI.

[awneil]

tadanohito said:

I can't change the board.

You don't need to change the board for your final project.

What I'm saying is that before you start on that board, you should spend some time on the Nordic Dev Kits getting used to the product, the SDK and the tools.

After you've done that, you will then be in a position to move on to the 3rd-party board.

It's always best to take small steps at a time - don't try to do too much all at once.