nRF51822 QFAA, what should be correct ram setup? is it 0x1f80 or 0x5f80?

[kfcube]

nRF51822 QFAA

At first I set up the RAM size to 0x1F80, it works fine. However, after I try to use RTT to print log, I got the compile error: region RAM overflowed with stack

I saw the examples they are using 0x5F80. I tried and my board doesn't work anymore. 

My question is, what should be the correct RAM size for nRF51822 QFAA?

Thanks,

[skulkarni]

Usually when the RAM is insufficient it will tell you adjust the RAM settings on the console.

 https://devzone.nordicsemi.com/f/nordic-q-a/33413/insufficient-ram-allocated-for-the-softdevice-in-nrf_sdh_ble_enable

[kfcube]

Thanks but this is not helpful. I am still using SDK11.0 and there are no such setting and prompt you mentioned in my version. Please let me know how to do in my circumstances. 

Thanks,

[skulkarni]

I don't have SDK11.0, what you can do is increment the RAM start in 1024Bytes.. At some point your program will not crash.. You can use that as reference.

[kfcube]

Thanks. I tried to increase but my board doesn't work anymore. So my question is, for 51822 QFAA, what should be the right RAM size to set up?