Combining BLE NUS and Buttonless DFU

[Shiv]

Hi everyone,

I am trying to use Buttonless DFU to reprogram the NRF 52 dev kit OTA. I had posted a question on the forum and had solved that problem:
devzone.nordicsemi.com/.../191437

I am now trying to combine my BLE NUS app with buttonless DFU without much success. It compiles without error but will not run. I tried the sample ble_app_uart instead and I am getting the same result. Which makes me think, I am doing it wrong. These are the changes.

1. In main.c:
static ble_uuid_t m_adv_uuids[]          =                                          /**< Universally unique service identifier. */
{
    {BLE_UUID_DEVICE_INFORMATION_SERVICE, BLE_UUID_TYPE_BLE},
    {BLE_UUID_NUS_SERVICE, NUS_SERVICE_UUID_TYPE}
};
I added the DFU service UUID.

2. In services_init in main.c, I added:
    ble_dfu_buttonless_init_t dfus_init = {0};
    dfus_init.evt_handler = ble_dfu_evt_handler;
    err_code = ble_dfu_buttonless_init(&dfus_init);
    APP_ERROR_CHECK(err_code);

3. In the main of main.c:
    // Initialize the async SVCI interface to bootloader before any interrupts are enabled.
    err_code = ble_dfu_buttonless_async_svci_init();
    APP_ERROR_CHECK(err_code);

4. In sdk_config.h:
#define NRF_SDH_BLE_VS_UUID_COUNT 2

5. In ble_app_uart_gcc_nrf52.ld, there is:
RAM (rwx) :  ORIGIN = 0x20002a98, LENGTH = 0xd568

Should I change this and if so to what number?

The code works only when I comment out all the DFU parts and make NRF_SDH_BLE_VS_UUID_COUNT=1.

Searching through forums, the answers have been to change NRF_SDH_BLE_VS_UUID_COUNT to 2 and increase RAM. But I have been playing around with these values without result for a day. Attached the entire code just in case.

Thanks in advance.

[Shiv]

Sorry, the attachment did not load.ble_app_uart_modified.zip

[Shiv]

Again, sorry for multiple posts. But the problem has been solved. I used this link:

https://devzone.nordicsemi.com/f/nordic-q-a/48190/how-to-switch-from-dfu-mode-to-start-nordic-uart-service

I am using Segger Embedded Studio to compile. In my project, I went to Options->Private Configurations -> Common -> Section Placement Macros and changed:

RAM_START=0x20002a98

to

RAM_START=0x20002aa8

So, the RAM start had to be moved. The RAM size is the same. So, is some code being dumped in the RAM before the application? And so, that code is not having sufficient space resulting in an overflow and thus my application is not being programmed?

[Einar Thorsrud]

Hi,

The reason for changing the RAM start address is if you modify the SoftDevice configuration so that the SoftDevice needs more RAM. The RAM is split so that the SoftDevice uses the lower parts of the RAM, and the application the highest. See Adjustment of RAM and Flash memory for details.

[Shiv]

That is a very useful tutorial. Thank you so much.