MCF548x Reference Manual, Rev. 3
22-52 Freescale Semiconductor

Figure 22-37. AESU Status Register (AESSR)

Table 22-35 describes AESU status register fields.

31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
R00HALTIFWOFRIEIDRD00000000
W
Reset0000000000000000
1514131211109876543210
R0000000000000000
W
Reset0000000000000000
Reg
Addr
MBAR + 0x32028

Table 22-35. AESSR Field Descriptions

Bits Name Description
31--30 — Reserved
29 HALT Halt. Indicates that the AESU has halted due to an error.
0 AESU not halted
1 AESU halted
Note: Because the error causing the AESU to stop operating may be masked to the
interrupt status register, the status register is used to provide a second source of
information regarding errors preventing normal operation.
28 IFW Input FIFO Writable. The controller uses this signal to determine if the AESU can accept
the next BURST SIZE block of data.
0 AESU Input FIFO not ready
1 AESU Input FIFO ready
Note: The SEC implements flow control to allow larger than FIFO sized blocks of data to
be processed with a single key/IV. The AESU signals to the crypto-channel that a ‘burst
size’ amount of space is available in the FIFO.
27 OFR Output FIFO Readable. The controller uses this signal to determine if the AESU can source
the next burst size block of data.
0 AESU Output FIFO not ready
1 AESU Output FIFO ready
Note: The SEC implements flow control to allow larger than FIFO sized blocks of data to
be processed with a single key/IV. The AESU signals to the crypto-channel that a “Burst
Size” amount of data is available in the FIFO.
26 IE Interrupt Error.This status bit reflects the state of the ERROR interrupt signal, as sampled
by the controller interrupt status register (Section 22.6.4.4, “SEC Interrupt Status Registers
(SISRH and SISRL)”).
0 AESU is not signaling error
1 AESU is signaling error