USBD BLE UART Example - Central

Question

Hi, 
 I am using Laird's BL654 USB dongle based on the nrf52840 and would like to convert the peripheral USBD BLE UART example ( https://infocenter.nordicsemi.com/index.jsp?topic=%2Fcom.nordic.infocenter.sdk5.v15.3.0%2Fusbd_ble_uart_example.html ) to act as a central device. I noticed a number of users on the forums have attempted something similar. However, I am new to the Nordic ecosystem of processors and BLE for that matter (coming from TI) and would like some proper guidance from Nordic regarding what they think is the best approach. 
 If I were to take a guess, I'd probably narrow down the differences between ble_app_uart (peripheral) and usbd_ble_uart and then copy those differences into ble_app_uart_c example? 
 Regards, 
 Robert

Sigurd · Accepted Answer

Hi, 
 I believe the easiest approach would be to take the usbd_ble_uart example, and replace the ble_app_uart specific part of the code with the ble_app_uart_c code. 
 That said, you can find a central version of the usbd_ble_uart example attached in this post (for SDK 15.3). I recommend to use the Segger Embedded Studio (SES) project. Note that if you are using a newer version of SES, you need to set NRF_FPRINTF_FLAG_AUTOMATIC_CR_ON_LF_ENABLED to 0 in sdk_config.h in order to get RTT logging working correctly(useful if using a DK).

Sigurd · Answer

Ideally, the project should be ported to SDK 16. But porting the project to use the newest SoftDevice should be straightforward. Looking at the s140_nrf52_7.0.1_migration-document.pdf, some PPI macros are changed, and BLE_COMMON_OPT_ADV_SCHED_CFG is removed, but this project are not using those. 
 So to migrate to SoftDevice v7.0.1, replace the headers found in SDK_15_3_folder\components\softdevice\s140\headers , with the new S140 v7.0.1 headers. 
 Then, in the SES project, change FLASH_START from 0x26000 to 0x27000, and set FLASH_SIZE=0xd9000 
 Also change RAM_START and RAM_SIZE according to this figure: 
 
 Might also want the loader to point to the new SD version: 
 
 Then recompile the application.

USBD BLE UART Example - Central

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