MCF548x Reference Manual, Rev. 3
9-2 Freescale Semiconductor

9.3.1 Module Base Address Register (MBAR)

The supervisor-level MBAR, Figure 9-1, specifies the base address and allowable access types for all
internal peripherals. It is written with a MOVEC instruction using the CPU address 0xC0F (refer to the
ColdFire Family Programmers Reference Manual). MBAR can be read or written through the debug
modules as a read/write register, as described in Chapter 8, “Debug Support.” Only the debug module can
read MBAR.
The MBAR is initialized to 0x8000_0000 at reset; however, it can be relocated to a new base address. To
access internal peripherals, write MBAR with the appropriate base address (BA) after system reset.
All internal peripheral registers occupy a single relocatable memory block along 256-KByte boundaries.
MBAR[BA] is compared to the upper 14 bits of the full 32-bit internal address to determine if an internal
peripheral is being accessed. Any accesses in this range, whether to a valid peripheral address or not, will
be made internally rather than using the external bus.
NOTE
The MBAR region must be mapped to non-cacheable space.
Table 9-1. SIU Register Map
Address
(MBAR +) Name Byte0 Byte1 Byte2 Byte3 Access
CPU+0xC0F Module Base Address Register MBAR R/W
0x04 SDRAM Drive Strength Register1
1The SDRAM Drive Strength and Chip Select Configuration registers are discussed in Chapter 18, “SDRAM Controller
(SDRAMC). They are shown in this memory map for reference purposes.
SDRAMDS1R/W
0x08–0x0C Reserved
0x10 System Breakpoint Control Regis-
ter
SBCR R/W
0x1–0x1C Reserved
0x20 SDRAM Chip Select 0
Configuration Register1CS0CFG01R/W
0x24 SDRAM Chip Select 1
Configuration Register1CS1CFG11R/W
0x28 SDRAM Chip Select 2
Configuration Register1CS2CFG21R/W
0x2C SDRAM Chip Select 3
Configuration Register1CS3CFG31R/W
0x30–0x34 RESERVED
0x38 Sequential Access Control Register SECSACR R/W
0x3C–0x40 RESERVED
0x44 Reset Status Register RSR R/W
0x48–0x4C RESERVED
0x50 JTAG Device Identification Number JTAGID R