Motorola ColdFire MCF5281 - Manual (Page 165)

System Control Module (SCM)
Freescale Semiconductor 8-13
8.6.3.1 Master Privilege Register (MPR)
The MPR specifies the access privilege level associated with each bus master in the platform. The register
provides one bit per bus master, where bit 3 corresponds to master 3 (Fast Ethernet Controller, not used on
MCF5216 and MCF5214), bit 2 to master 2 (DMA Controller), bit 1 to master 1 (internal bus master), and
bit 0 to master 0 (ColdFire core).
Only trusted bus masters can modify the access control registers. If a non-trusted bus master attempts to
write any of the SACU control registers, the access is aborted with an error termination and the registers
remain unaffected.
The processor core is connected to bus master 0 and is always treated as a trusted bus master. Accordingly,
MPR[0] is forced to 1 at reset.
8.6.3.2 Peripheral Access Control Registers (PACR0–PACR8)
Access to several on-chip peripherals is controlled by shared peripheral access control registers. A single
PACR defines the access level for each of the two modules. These modules only support operand reads
Table 8-7. SACU Register Memory Map
IPSBA
R
Offset
[31:28] [27:24] [23:20] [19:16] [15:12] [11:8] [7:4] [3:0]
0x020 MPR — — — — — —
0x024 PACR0 PACR1 PACR2 PACR3
0x028 PACR4 — PACR5 PACR6
0x02c PACR7 — PACR8 —
0x030 GPACR0 GPACR1 — —
0x034 — — — —
0x038 — — — —
0x03C — — — —
7 0
Field — MPR[3:0]
Reset 0000_0011
R/W R/W
Address IPSBAR + 0x020
Figure 8-8. Master Privilege Register (MPR)
Table 8-8. MPR[n] Field Descriptions
Bits Name Description
7–4 — Reserved. Should be cleared.
3–0 MPR Each 1-bit field defines the access privilege level of the given bus master n.
0 All bus master accesses are in user mode.
1 All bus master accesses use the sourced user/supervisor attribute.
MCF5282 and MCF5216 ColdFire Microcontroller User’s Manual, Rev. 3