how to solve an error which happened for registration of many BLE services

Question

As shown in subject, I tried to register many BLE services, DIS, BAS, HTS, and Custom Service. Then nRF52832(and nrf52840 preview) has stopped by an error of NRF_ERROR_NO_MEM. I guess the system has not enough memory for registration of many BLE service, because no error happened if decreases BLE services. but I don't know how to increase memory for BLE services. 
 Of course I tried to change RAM_START and RAM_SIZE, but NRF_ERROR_NO_MEM stll happened. could anyone tell me how to increase memory for BLE services?

bjorn-spockeli · Accepted Answer

Hi Yoshihiro,

could you state which function specifically that returns NRF_ERROR_NO_MEM?

If its sd_ble_uuid_vs_add that returns NRF_ERROR_NO_MEM then there are no more free VS UUID slots. If you're adding a custom service then you have to make sure that the Vendor Specific UUID count in sdk_config.h, NRF_SDH_BLE_VS_UUID_COUNT , is set to the number of custom services you are adding.

If it is sd_ble_gatts_service_add or sd_ble_gatts_characteristic_add or sd_ble_gatts_descriptor_add that returns NRF_ERROR_NO_MEM, then you're likely exceeding the default GATT table size set in the sdk_config.h file, NRF_SDH_BLE_GATTS_ATTR_TAB_SIZE. Try increasing it, but remember to adjust the RAM_START and RAM_SIZE accordingly.

SoftDevice will actually tell you if you have allocated to little RAM, i.e. it will return the application RAM start address. You can start a debug session with a breakpoint after the sd_ble_enable() call in nrf_sdh_ble_enable() in nrf_sdh_ble.c

If you have RTT logging enabled( should be enabled by default in the ble_app_template example) then the RTT output will be displayed in the Debug Terminal in Segger Embedded Studio or in Segger RTT Viewer if your using another IDE.

<warning> nrf_sdh_ble: Insufficient RAM allocated for the SoftDevice.
<warning> nrf_sdh_ble: Change the RAM start location from 0x20002210 to 0x20002220.
<warning> nrf_sdh_ble: Maximum RAM size for application is 0xDDE0.
<error> nrf_sdh_ble: sd_ble_enable() returned NRF_ERROR_NO_MEM.
<error> app: ERROR 4 [NRF_ERROR_NO_MEM] at C:\Nordic_Semiconductor\SDK_Repository\nRF5_SDK\nRF5_SDK_15.0.0_a53641a\examples\ble_peripheral\custom_ble_service_example\main.c:663
PC at: 0x0002EF37

It is also possible to use the UART backend instead of the RTT backend by setting
NRF_LOG_BACKEND_RTT_ENABLED to 0 and NRF_LOG_BACKEND_UART_ENABLED to 1 in sdk_config.h.
In both cases you'll see the following output in the Debug Terminal/Serial TErminal/RTT Viewer if you have allocated to little RAM for the SoftDevice.

Yoshihiro Goto · Answer

Hello Bjorn, 
 Great! Finally I have solved this problem. it changes the value of NRF_SDH_BLE_GATTS_ATTR_TAB_SIZE from 1408(default) to 2000. 
 Thanks for your splendid advice.