Motorola ColdFire MCF5281 - Manual (Page 117)

ColdFire Flash Module (CFM)
Freescale Semiconductor 6-5
6.3.1 CFM Configuration Field
The CFM configuration field comprises 24 bytes of reserved array memory space that determines the
module protection and access restrictions out of reset. Data to secure the Flash from unauthorized access
is also stored in the CFM configuration field.
Table 6-1 describes each byte used in this field.
6.3.2 Flash Base Address Register (FLASHBAR)
The configuration information in the Flash base address register (FLASHBAR) controls the operation of
the Flash module.
• The FLASHBAR holds the base address of the Flash. The MOVEC instruction provides write-only
access to this register.
• The FLASHBAR can be read or written from the debug module in a similar manner.
• All undefined bits in the register are reserved. These bits are ignored during writes to the
FLASHBAR, and return zeroes when read from the debug module.
• The back door enable bit, FLASHBAR[BDE], is cleared at reset, disabling back door access to the
Flash.
• The FLASHBAR valid bit is programmed according to the chip mode selected at reset (see
Chapter 27, “Chip Configuration Module (CCM) ” for more details). All other bits are unaffected.
The FLASHBAR register contains several control fields. These fields are shown in Figure 6-3
NOTE
The default value of the FLASHBAR is determined by the chip
configuration selected at reset (see
Chapter 27, “Chip Configuration
Module (CCM) ” for more information). If external boot mode is used, then
the FLASHBAR located in the processor’s CPU space will be invalid and it
must be initialized with the valid bit set before the CPU (or modules) can
access the on-chip Flash.
Table 6-1. CFM Configuration Field
Address Offset (from array
base address)
Size
in Bytes
Description
0x0000_0400–0x0000_0407 8 Back door comparison key
0x0000_0408–0x0000_040B 4 Flash program/erase sector protection
Blocks 0H/0L (see
Section 6.3.4.4, “CFM Protection Register
(CFMPROT) ”)
0x0000_040C–0x0000_040F 4 Flash supervisor/user space restrictions
Blocks 0H/0L (see
Section 6.3.4.5, “CFM Supervisor Access Register
(CFMSACC) ”)
0x0000_0410–0x0000_0413 4 Flash program/data space restrictions
Blocks 0H/0L (see
Section 6.3.4.6, “CFM Data Access Register
(CFMDACC) ”)
0x0000_0414–0x0000_0417 4 Flash security longword (see Section 6.3.4.3, “CFM Security Register
(CFMSEC) ”)
MCF5282 and MCF5216 ColdFire Microcontroller User’s Manual, Rev. 3