How to run UART/Serial Port Emulation over BLE on SDK v14.2.0?

[Jian Li]

I try to run UART/Serial Port Emulation over BLE on SDK v14.2.0 with nRF52 DK and nRF Connect on Android phone following link "http://infocenter.nordicsemi.com/index.jsp?topic=%2Fcom.nordic.infocenter.sdk5.v12.2.0%2Fble_sdk_app_nus_c.html&cp=4_0_1_4_2_0_2". I compile and download example code with softdevice S132, the phone detect Nordic-Uart, and connected, but nothing more than that, if I try to send something, BLE will disconnected, even it will be re-connected if requested. I run Tera Term on PC, it shows Nordic-UART, but does not show anymore thing, no response to keyboard. There are some code displayed in this link, they are said added to be added in softdevice, it is not clear that they are already added and I do not have to add them in again, if that is the case, why they are displayed here. If not added, where they should be added, in main.c or ble_nus.c? Please help!

[Jørgen Holmefjord]

Hi,

You are linking the the NUS central application. It sounds like you want to use the peripheral application? Did you change anything in the example? Have you tested the precompiled HEX-file found in the hex directory in the example folder? Could you please post some screenshots showing the output of the terminal, etc.? You should not need to add anything to the example to get it working, the code in the link explains how you can use the received strings to do things in the application. This is an extension to the application, and is not needed for the purpose of the example.

Best regards,
Jørgen

[Jørgen Holmefjord]

I see there is a bug in the example. Please have a look at this answer.

[Jian Li]

Hi, Jorgen: Thank you for help. I did two changes:

1. change

err_code = nrf_ble_gatt_att_mtu_periph_set(&m_gatt, 64);

to err_code = nrf_ble_gatt_att_mtu_periph_set(&m_gatt, BLE_GATT_ATT_MTU_DEFAULT); in gatt_init(void);

2. Change 

#define NRF_SDH_BLE_GATT_MAX_MTU_SIZE 247 to 
#define NRF_SDH_BLE_GATT_MAX_MTU_SIZE 23 in file sdk_config.h

then re-compile and download, the response in SES are: <info> app: Disconnected
<error> app: ERROR 8198 [Unknown error code] at C:\nRF52\nRF5_SD,

is there more change should be done?

Good night, see you later!

[Jørgen Holmefjord]

Do you get this error immediately, or after a while? Error code 8198 = 0x2006 = NRF_ERROR_SOC_POWER_OFF_SHOULD_NOT_RETURN. If you are running the application in debug mode (debug mode will be enabled when debugging or after programming the application), the application can enter emulated system off mode, which will make the function sd_power_system_off() return and cause this error.

[Jian Li]

Good morning, Jorgen. Thank you for help!

I re-test it by compiling in release mode, the error does not appear. But nRF UART in my  phone shows " The device does not support UART, disconnected", here is screenshot of my device, it is Android 5.1.1. I try nRF Connect, it works with other examples like Heart and Blinky, but cannot connect to UART emulator in client mode, in Server tab, it could show two generic access as shown in screenshot 2 as follows:

 

 What is phone OS requirements for nRF URAT V2.0? I remember nRF Connect works in Android 5, am I right? Any other phone app available for me to try?

I  also try desk version of nRF Connect, it responses cannot find COM port, Tera Term can find and open the com port, why nRF Connect cannot?