ram resource requirements

Hi delay_7,

You can find out the RAM required for the softdevice by looking at the p_app_ram_base that's output from the sd_ble_enable() function. 
You can see this in the description of sd_ble_enable() function: 

* @param[in, out] p_app_ram_base Pointer to a variable containing the start address of the application RAM region (APP_RAM_BASE). On return, this will contain the minimum start address of the application RAM region  required by the SoftDevice for this configuration.

What you can do is to printout p_app_ram_start after sd_ble_enable() call in nrf_sdh_ble_enable() in nrf_sdh_ble.c. Similar to what we do here when the ram on configured for the softdevice is not sufficient: 

thanks your reply.it`s useful.but i want to estimate the ram before developing project.when adding a device infomation services 、battery services or custom services as a central.Is there any relevant experience parameters, such as how much ram will be required by adding a nus.

Thanks again

Hi Delay 7,

It's pretty much depends on the service and the characteristic. 
The easiest way to estimate that is to actually test using our project. You will have a rough idea of how many bytes needed for a certain service/characteristic. 

ok，i will try to test ,

Thanks.