RE: issue with nRF52811 and S140 softdevice

Amanda Hsieh — Thu, 16 Sep 2021 11:12:06 GMT

Hi,

Good to know you fix the issue. The minimum required memory of S140 is 5.6 kB (0x1678 bytes) that means the SD basically require. In other words, SD need more than that if the application run some features like increase NRF_SDH_BLE_VS_UUID_COUNT or link count. In that situation, You will get this in the log:
<warning> nrf_sdh_ble: Change the RAM start location from 0x20002A38 to 0x20002A48.
<warning> nrf_sdh_ble: Maximum RAM size for application is 0x3D5B8.

Then, refer to the log to modify RAM_START and RAM_SIZE.

Regards,
Amanda

RE: issue with nRF52811 and S140 softdevice

Remi P. — Thu, 16 Sep 2021 08:19:54 GMT

ok i have found the issue apparently the ram start is different depending on the target device i found in another thread that one has to set RAM_START=0x20002a38;RAM_SIZE=0x35c8 for the nrf52811 it seems the soft device use 0x800 more than what is configured in the project. The example is now working but I think you should advertise exactly which value to set as ram start in the release notes of S140 because you write it needs 1.75kb ram stack (0x700) and 5.6kb ram (0x1678) minimum but in fact needs 10.8 kb (0x2a38). I understand it depends on what is activated but still why a 0x2260 is enough when working on a nrf52840 and not on a nrf52811.
What would be great is a tool to estimate ram usage of softdevice depending on features activated or deactivated.