53.4.8.1 Manual Mode

The sequence of actions is as follows:

1. Write AES_MR with all required fields, including but not limited to SMOD and OPMOD. (Write AES_EMR.PKRS according to the type of key to be loaded).
2. Write the 128-bit/192-bit/256-bit AES key in AES_KEYWRx or in the Private Key internal registers.
3. Write the initialization vector (or counter) in AES_IVRx.
   Note: AES_IVRx concerns all modes except ECB.
4. Set the bit DATRDY (Data Ready) in the AES Interrupt Enable register (AES_IER), depending on whether an interrupt is required or not at the end of processing.
5. Write the data to be encrypted/decrypted in the authorized AES_IDATARx (see the following table).
6. Set the START bit in the AES Control register (AES_CR) to begin the encryption or the decryption process.
7. When processing completes, the DATRDY flag in the AES Interrupt Status register (AES_ISR) is raised. If an interrupt has been enabled by setting AES_IER.DATRDY, the interrupt line of the AES is activated.
8. When software reads one of AES_ODATARx, AES_IER.DATRDY is automatically cleared.