Dynamic updating of serial number in device ID

Question

Ole,
I am trying to update the serial number value in an already initialized standard Device ID profile.
[i]dis_init.serial_num_str.length = (uint16_t)strlen(newserial);
dis_init.serial_num_str.p_str = (uint8_t *)newserial;
err_code = ble_dis_update(&dis_init);[/i] 
 and this
[i]uint32_t ble_dis_update(const ble_dis_init_t * p_dis_init){
uint32_t err_code; 
 if (p_dis_init->serial_num_str.length > 0) {
 err_code = char_add(BLE_UUID_SERIAL_NUMBER_STRING_CHAR,
 p_dis_init->serial_num_str.p_str, 
 p_dis_init->serial_num_str.length,
 &p_dis_init->dis_attr_md,
 &serial_num_handles);
 if (err_code != NRF_SUCCESS) {
 return err_code;
 }
}
return NRF_SUCCESS;
 
 }[/i]
And while nothing throws an error, it also doesn't update the value. Any ideas? 
 Another option I have here is to use a soft reset to start the system over again, and I may have a use for that anyway, so I have search through a the documentation but I cant seem to find a way to force a reset. Is inline with a jump to the reset vector the only way, or is there something a little more elegant?

Ole Morten · Accepted Answer

I'm having a little trouble understanding this code snippet. To update an existing characteristic, you should make sure to use sd_ble_gatts_value_set(), which require you to have the handle of the characteristic you want to set. Without having tested, I'd therefore suggest a method something like this 
 
uint32_t ble_dis_serial_num_update(char * serial_num_string, uint8_t length)
{
 return sd_ble_gatts_value_set(serial_num_handles.value_handle, 0, length, serial_num_string);
}

 
 Also, you should be aware that you can't add a characteristic to a service if other services have been added in the mean time. Any attribute added will always be added to the last service added, no matter what you set the service_handle to in the sd_ble_gatts_characteristic_add() function. This is a limitation with the current GATT Table implementation in the S110. 
 Edit: To also answer the second part, you can use NVIC_SystemReset() or sd_nvic_SystemReset(), depending on whether the softdevice is enabled or not.

Dynamic updating of serial number in device ID

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