Motorola MCF5281, MCF5282 user manual CFM Configuration Field, Flash Base Address Register Flashbar

Models: MCF5282 MCF5281

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Memory Map

The CFM module has hardware interlocks to protect data from accidental corruption. The CFM memory array is logically divided into 16-Kbyte sectors for the purpose of data protection and access control. A flexible scheme allows the protection of any combination of logical sectors (see Section 6.3.4.4, “CFM Protection Register (CFMPROT)”). A similar mechanism is available to control supervisor/user and program/data space access to these sectors.

6.3.1CFM 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 6-1describes each byte used in this field.

Table 6-1. CFM Configuration Field

Address Offset (from array base

Size

Description

address)

in Bytes

 

 

 

 

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)”)

 

 

 

6.3.2Flash 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.

MOTOROLA

Chapter 6. ColdFire Flash Module (CFM)

6-5

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Motorola MCF5281, MCF5282 user manual CFM Configuration Field, Flash Base Address Register Flashbar