Adding NUS to existing profile - how to get a 'link context' ?

RE: Adding NUS to existing profile - how to get a 'link context' ?

eyalasko — Sat, 28 Dec 2019 22:26:31 GMT

So, to wrap up the story -

Eventually, it was a packing problem indeed but on my side.

There was one occurrence of #pragma pack(push) without matching #pragma pack(pop)... 😨

I hope this can help any fellow developer banging his head as I did.

Happy new year everybody.

RE: Adding NUS to existing profile - how to get a 'link context' ?

eyalasko — Sat, 28 Dec 2019 18:00:26 GMT

Reviving this post...

I've tried to increase freeRTOS macros. Still the same phenomena.

I'm not sure if its relevant, but I have 2 custom services unlike the demo NUS project which has only 1.

Attaching a memory dump screenshot - a picture worth 1000 words...

Thanks

RE: Adding NUS to existing profile - how to get a 'link context' ?

Sigurd — Fri, 09 Aug 2019 08:41:59 GMT

I have not been able to reproduce this. Could you try to increase(maybe double) the below values in your FreeRTOSConfig.h file to see if that helps?

#define configMINIMAL_STACK_SIZE
#define configTOTAL_HEAP_SIZE

If that does not help, could you upload a project that reproduces the issue ?

RE: Adding NUS to existing profile - how to get a 'link context' ?

eyalasko — Tue, 09 Jul 2019 20:00:27 GMT

[quote userid="77782" url="~/f/nordic-q-a/49151/adding-nus-to-existing-profile---how-to-get-a-link-context/197154"]you would need to allocate more RAM to the SoftDevice.[/quote]

I did. Otherwise one if the sd calls would have asserted (probably sd_ble_uuid_vs_add())

[quote userid="77782" url="~/f/nordic-q-a/49151/adding-nus-to-existing-profile---how-to-get-a-link-context/197154"]Which version of SDK do you use?[/quote]

SDK 15.2, nRF52832, a project that is based on ble_app_hrs_freertos example

[quote userid="77782" url="~/f/nordic-q-a/49151/adding-nus-to-existing-profile---how-to-get-a-link-context/197154"]Could you provide the J-Link RTT log?[/quote]

Attached RTT Client prints (after turning on BLE_NUS_CONFIG_LOG_ENABLED in sdk_config.h)

###RTT Client: ************************************************************
###RTT Client: *               SEGGER Microcontroller GmbH                *
###RTT Client: *   Solutions for real time microcontroller applications   *
###RTT Client: ************************************************************
###RTT Client: *                                                          *
###RTT Client: *       (c) 2012 - 2016  SEGGER Microcontroller GmbH       *
###RTT Client: *                                                          *
###RTT Client: *     www.segger.com     Support: support@segger.com       *
###RTT Client: *                                                          *
###RTT Client: ************************************************************
###RTT Client: *                                                          *
###RTT Client: * SEGGER J-Link RTT Client   Compiled Aug 30 2018 17:38:24 *
###RTT Client: *                                                          *
###RTT Client: ************************************************************

###RTT Client: -----------------------------------------------
###RTT Client: Connecting to J-Link RTT Server via localhost:19021 .... Connected.
SEGGER J-Link V6.46 - Real time terminal output
J-Link OB-SAM3U128-V2-NordicSemi compiled Jan  7 2019 14:07:15 V1.0, SN=682324592
Process: UV4.exe
<info> app: *** myApp started [Jul  9 2019 22:52:34] ***
<info> app: <<<===  myApp 0.20.28.CF771A (Jul  9 2019 22:52:34) starting... ===>>>
<info> app: *** myApp started [Jul  9 2019 22:52:34] ***
<info> app: <<<===  myApp 0.20.28.CF771A (Jul  9 2019 22:52:34) starting... ===>>>
<info> app: Fast advertising.
<warning> app:  !! Pulse fault: status code = 0x40
<warning> app:     Pulse fault cleared
<error> hardfault: HARD FAULT at 0x0002E286                //  << This line triggered on connection
<error> hardfault:   R0:  0x00000000  R1:  0x00000000  R2:  0x200067F0  R3:  0x00000000
<error> hardfault:   R12: 0x000001F3  LR:  0x0003886F  PSR: 0x61000000
<error> hardfault: Cause: Data bus error (PC value stacked for the exception return points to the instruction that caused the fault).
<error> hardfault: Bus Fault Address: 0x00200028

RE: Adding NUS to existing profile - how to get a 'link context' ?

Amanda Hsieh — Mon, 08 Jul 2019 13:31:42 GMT

Hi,

After adding NUS to the project, you would need to allocate more RAM to the SoftDevice.

Which version of SDK do you use?

Could you provide the J-Link RTT log?

-Amanda H.

RE: Adding NUS to existing profile - how to get a 'link context' ?

eyalasko — Mon, 08 Jul 2019 11:20:14 GMT

Hi,

NRF_SDH_BLE_VS_UUID_COUNT is set to 2 (see OP) as I have a proprietary service + NUS.

Any insight about the 'packing' issue described above?

Thanks

RE: Adding NUS to existing profile - how to get a 'link context' ?

Amanda Hsieh — Mon, 08 Jul 2019 11:04:12 GMT

Hi,

Please check sdk_config.h. NRF_SDH_BLE_VS_UUID_COUNT parameter should be greater than zero

Softdevice should be configured to accept Vendor Specific UUIDs, like NUS Nordic UART Service.

-Amanda H.

RE: Adding NUS to existing profile - how to get a 'link context' ?

eyalasko — Fri, 05 Jul 2019 08:19:34 GMT

I may have found the root cause (still not a workaround).

The problem lies in the call to ble_nus_init() from services_init().

It seems that m_nus is handled as PACKED structure on services_init() but as UNPACKED structure when its pointer is passed to ble_nus_init().

Is it an IDE issue ???

Note the members addresses in the attached screen cap

RE: Adding NUS to existing profile - how to get a 'link context' ?

eyalasko — Fri, 05 Jul 2019 07:29:35 GMT

Hi Amanda,

I've followed your advice.

The structure is indeed initialized upon program startup and its been overwritten in the call to ble_nus_init(), without being detected because it returns NRF_SUCCESS.

I've digged deeper and found that the problem occurs after the service is added when the first characteristic (BLE_UUID_NUS_RX_CHARACTERISTIC) is added (on the call to sd_ble_gatts_characteristic_add() in characteristic_add())

I've increased RAM_ADDRESS_START (by more than 1000 bytes) just in case its a memory problem but the problem remains.

Please note that, as I've mentioned above, there is no error code returned (NRF_SUCCESS).

RE: Adding NUS to existing profile - how to get a 'link context' ?

Amanda Hsieh — Thu, 04 Jul 2019 10:51:42 GMT

Hi,

BLE Link Ctx storage instance is created together with the NUS service instance. p_link_ctx_storage->p_ctx_data_pool can never be null because its populated during Ctx storage variable declaration in the macro. p_ctx_data_pool gets the value on the connected callback in the ble_nus.c file: on_connect().

p_link_ctx_storage->p_ctx_data_pool is not changed anywhere in the code and it's a constant pointer so we would get a warning if somebody tried to overwrite it.

It's hard to say what causes it. It would be useful to track if some other part of the software accidentally resets this part of memory to NULL. You can check if p_ctx_data_pool is non-null after NUS initialization.

-Amanda H.

RE: Adding NUS to existing profile - how to get a 'link context' ?

eyalasko — Tue, 02 Jul 2019 19:24:26 GMT

Hi Amanda,

p_link_ctx_Storage is not null but it has a null member that causes the crash: p_link_ctx_storage->p_ctx_data_pool.

It crashes at the highlighted line in the screen cap below which is the first line in ble_nus.c on_connect()

RE: Adding NUS to existing profile - how to get a 'link context' ?

Amanda Hsieh — Tue, 02 Jul 2019 12:27:00 GMT

Hi,

What value does blcm_link_ctx_get() return? If p_link_ctx_storage is NULL or contains a NULL pointer, or if pp_ctx_data is NULL, it will return NRF_ERROR_NULL instread of crash.

For BLE Link Context Manager, you can refer to <nRF5_SDK>\examples\ble_peripheral\ble_app_uart for the usuage.

Best regards,

Amanda H.

RE: Adding NUS to existing profile - how to get a 'link context' ?

eyalasko — Mon, 01 Jul 2019 19:45:24 GMT

Hi,

I've added the following line at the beginning of main.c (it wouldn't build otherwise)

BLE_NUS_DEF(m_nus, NRF_SDH_BLE_TOTAL_LINK_COUNT);

and the following snippet in services_init() -

   // Initialize NUS.
    memset(&nus_init, 0, sizeof(nus_init));

    nus_init.data_handler = nus_data_handler;

    err_code = ble_nus_init(&m_nus, &nus_init);
    APP_ERROR_CHECK(err_code);

RE: Adding NUS to existing profile - how to get a 'link context' ?

goldwake — Mon, 01 Jul 2019 00:33:31 GMT

are you calling

BLE_NUS_DEF(ble_nus, TOTAL_NUM_CONNECTIONS)

anywhere?