61.4.4 Double Input Buffer

The SHA Input Data registers (SHA_IDATARx) can be double-buffered to reduce the runtime of large messages.

Double-buffering allows a new message block to be written while the previous message block is being processed. This is only possible when DMA accesses are performed (SMOD = 2).

The DUALBUFF bit in the SHA_MR must be set to have double input buffer access.