Flash Base Address Register (Flashbar); Flashbar Field Descriptions - Motorola ColdFire MCF5281 User Manual

31 30
Field BA31 BA30 BA29 BA28 BA27 BA26 BA25 BA24 BA23 BA22 BA21 BA20 BA19
Reset
R/W
15
Field
Reset
R/W R/W
Address
Note: The reset value for the valid bit is determined by the chip mode selected at reset (see Chapter 30, "Chip
Configuration Module (CCM)").
Figure 6-3. Flash Base Address Register (FLASHBAR)
Bits Name
31–19 BA[31:18]
18–9 —
8 WP
7–6 —
5–1 C/I, SC, SD, UC,
UD
0
MOTOROLA
29 28 27 26
—
0000_0001_0010_000
R
Table 6-2. FLASHBAR Field Descriptions
Base address field. Defines the 0-modulo-512K base address of the Flash module. By
programming this field, the Flash may be located on any 512Kbyte boundary within the
processor's four gigabyte address space.
Reserved, should be cleared.
Write protect. Allows only read accesses to the Flash. When this bit is set, any attempted
write access will generate an access error exception to the ColdFire processor core.
0 Allows read and write accesses to the Flash module
1 Allows only read accesses to the Flash module
Reserved, should be cleared.
Address space masks (ASn).
These five bit fields allow certain types of accesses to be "masked," or inhibited from
accessing the Flash module. The address space mask bits are:
C/I CPU space/interrupt acknowledge cycle mask
SC Supervisor code address space mask
SD Supervisor data address space mask
UC User code address space mask
UD User data address space mask
For each address space bit:
0 An access to the Flash module can occur for this address space
1 Disable this address space from the Flash module. If a reference using this address
space is made, it is inhibited from accessing the Flash module, and is processed like any
other non-Flash reference.
These bits are useful for power management as detailed in Section 5.3.4, "Power
Management.""
V Valid. When set, this bit enables the Flash module; otherwise, the module is disabled.
0 Contents of FLASHBAR are not valid
1 Contents of FLASHBAR are valid
Chapter 6. ColdFire Flash Module (CFM)
25 24 23 22 21
0000_0000_0000_0000
R/W
9 8 7 6
WP — C/I
R/W R
CPU + 0xC04
Description
Memory Map
20 19 18
—
5 4 3 2
SC SD UC UD
R/W
16
1 0
V
See
Note
6-7