SLAU846B June 2023 – November 2024 MSPM0G1105 , MSPM0G1106 , MSPM0G1107 , MSPM0G1505 , MSPM0G1506 , MSPM0G1507 , MSPM0G3105 , MSPM0G3106 , MSPM0G3107 , MSPM0G3505 , MSPM0G3506 , MSPM0G3507
The AES module contains four event publishers and no event subscribers. One event publisher (CPU_INT) manages AES interrupt requests (IRQs) to the CPU subsystem through a static event route. The second, third, and fourth event publishers (DMA_TRIG0, DMA_TRIG1, and DMA_TRIG2) can be used to publish AES events to the DMA through DMA event routes.
The AES events are summarized in Table 28-194.
Event | Type | Source | Destination | Route | Configuration | Functionality |
---|---|---|---|---|---|---|
CPU Interrupt Event | Publisher | AES | CPU Subsystem | Static route | CPU_INT registers | Fixed interrupt route from RTC to CPU |
DMA Trigger Event 0 | Publisher | AES | DMA | DMA route | DMA_TRIG 0 registers | DMA trigger 0 for block cipher modes |
DMA Trigger Event 1 | Publisher | AES | DMA | DMA route | DMA_TRIG 1 registers | DMA trigger 1 for block cipher modes |
DMA Trigger Event 2 | Publisher | AES | DMA | DMA route | DMA_TRIG 2 registers | DMA trigger 2 for block cipher modes |
In general, the CPU interrupt event is used to communicate completion of an AES operation to the CPU, and the DMA triggers are used together to implement the block cipher modes (ECB, CBC, OFB, and CFB) using the DMA together with the AES accelerator.
When the CMEN bit is set in AESACTL0, the AES module will trigger DMA trigger event 0, DMA trigger event 1, and DMA trigger event 2 to execute different block cipher modes of operation together with the DMA.
For example, when using ECB encryption with AESCMEN=0x1, DMA trigger event 0 is triggered four times for DMA word access to read out AESADOUT, and AES trigger 1 is triggered 4 times to fill the next data into AESADIN. The AES module generates a trigger for each word, and so the DMA must be configured in repeated single channel mode. See the block cipher mode section for details on how the DMA must be configured to support the ECB, CBC, OFB, and CFB block cipher modes.