S132: What effect does is_var_len have in the softdevice?

[jcormier]

The documentation simply says: 1 for variable length and 0 for fixed length.

What exactly does changing this do? Do I save space by setting it to fixed? Why does BDS set it to 1 by default.

[jcormier]

Thanks for the info. I think I answered the question myself. It would appear that since my notification characteristic doesn't always send 20 bytes of data (the last packet sent won't always be 20 Bytes aligned), that is_var_len needs to be set to true.