AES256 Registers
750
SLAU356I – March 2015 – Revised June 2019
Copyright © 2015–2019, Texas Instruments Incorporated
AES256 Accelerator
16.3.3 AESASTAT Register
AES Accelerator Status Register
Figure 16-16. AESASTAT Register
15
14
13
12
11
10
9
8
AESDOUTCNTx
AESDINCNTx
r-0
r-0
r-0
r-0
r-0
r-0
r-0
r-0
7
6
5
4
3
2
1
0
AESKEYCNTx
AESDOUTRD
AESDINWR
AEKEYWR
AESBUSY
r-0
r-0
r-0
r-0
r-0
rw-0
rw-0
r-0
Table 16-14. AESASTAT Register Description
Bit
Field
Type
Reset
Description
15-12
AESDOUTCNTx
R
0h
Bytes read through AESADOUT. Reset when AESDOUTRD is reset.
If AESDOUTCNTx = 0 and AESDOUTRD = 0, no bytes were read.
If AESDOUTCNTx = 0 and AESDOUTRD = 1, all bytes were read.
11-8
AESDINCNTx
R
0h
Bytes written through AESADIN, AESAXDIN or AESAXIN. Reset when
AESDINWR is reset.
If AESDINCNTx = 0 and AESDINWR = 0, no bytes were written.
If AESDINCNTx = 0 and AESDINWR = 1, all bytes were written.
7-4
AESKEYCNTx
R
0h
Bytes written through AESAKEY for AESKLx=00, half-words written through
AESAKEY if AESKLx = 01, 10, 11. Reset when AESKEYWR is reset.
If AESKEYCNTx = 0 and AESKEYWR = 0, no bytes were written.
If AESKEYCNTx = 0 and AESKEYWR = 1, all bytes were written.
3
AESDOUTRD
R
0h
All 16 bytes read from AESADOUT. AESDOUTRD is reset by PUC,
AESSWRST, an error condition, changing AESOPx, changing AESKLx, when
the AES accelerator is busy, and when the output data is read again.
0 = Not all bytes read
1 = All bytes read
2
AESDINWR
RW
0h
All 16 bytes written to AESADIN, AESAXDIN or AESAXIN. This bit can be
modified by software only if AESCMEN=0. Changing its state by software also
resets the AESDINCNTx bits.
AESDINWR is reset by PUC, AESSWRST, an error condition, changing
AESOPx, changing AESKLx, the start to (over)write the data, and when the AES
accelerator is busy. Because it is reset when AESOPx or AESKLx is changed it
can be set by software again to indicate that the current data is still valid.
0 = Not all bytes written
1 = All bytes written
1
AESKEYWR
RW
0h
All 16 bytes written to AESAKEY. This bit can be modified by software but it
must not be reset by software (1
→
0) if AESCMEN=1. Changing its state by
software also resets the AESKEYCNTx bits.
AESKEYWR is reset by PUC, AESSWRST, an error condition, changing
AESOPx, changing AESKLx, and the start to (over)write a new key. Because it is
reset when AESOPx is changed it can be set by software again to indicate that
the loaded key is still valid
0 = Not all bytes written
1 = All bytes written
0
AESBUSY
R
0h
AES accelerator module busy; encryption, decryption, or key generation in
progress.
0 = Not busy
1 = Busy