MCF548x Reference Manual, Rev. 3
22-28 Freescale Semiconductor
Table 22-17 describes the FRn fields.

22.7.1.5 Data Packet Descriptor Buffer (CDBUFn)

This bank of eight registers stores the header, followed by length/pointer pairs, followed by a next data
packet descriptor pointer. These registers fully describe the service the SEC is to perform. The header
indicates the precise service (Single-DES CBC encryption or generate random numbers are two
examples), and the length/pointer pairs indicate the number and location of data and context information
needed to complete the service.

22.8 ARC Four Execution Unit (AFEU)

This section contains details about the ARC Four Execution Unit (AFEU), including register details.

22.8.1 AFEU Register Map

The registers used in the AFEU are documented primarily for debug and target mode operations. The
AFEU contains the following registers:
Reset control register
Status register
Interrupt status register
Interrupt mask register

22.8.2 AFEU Reset Control Register (AFRCR)

This register, as shown in Figure 22-21, allows three levels of reset that effect the AFEU only, as defined
by three self-clearing bits. It should be noted that the AFEU executes an internal reset sequence for
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
R FETCH_ADDR
W
Reset0000000000000000
1514131211109876543210
R FETCH_ADDR
W
Reset0000000000000000
Reg
Addr
MBAR + 0x2204C (FR0), 0x2304C (FR1)
Figure 22-20. Fetch Register (FRn)
Table 22-17. FRn Field Descriptions
Bits Name Description
31–0 FETCH
ADDR
Fetch address. Pointer to system memory location of a descriptor the host wants the SEC to fetch.