mcf51jf128 Freescale Semiconductor, Inc, mcf51jf128 Datasheet - Page 550

• Manufacturer Part Number: mcf51jf128
• Description: Mcf51jf128 Reference Manual
• Manufacturer: Freescale Semiconductor, Inc

Reset
Memory Map/Register Definition
24.3.2 Chip select mask register (FB_CSMRn)
CSMRn registers specify the address mask and allowable access types for the respective
chip-selects.
Addresses: FB_CSMR0 is FFFF_E800h base + 4h offset = FFFF_E804h
550
Bit
W
R
Reserved
Reserved
31
0
31–16
BAM
15–9
Field
WP
7–1
30
V
8
0
0
FB_CSMR1 is FFFF_E800h base + 10h offset = FFFF_E810h
29
0
28
0
Base address mask
Defines the chip-select block size by masking address bits. Setting a BAM bit causes the corresponding
CSAR bit to be a don’t care in the decode.
The block size for FB_CSn is 2
For example, if CSAR0[BA] equals 0x8000 and CSMR0[BAM] equals 0x0007, FB_CS0 addresses one
512 KB memory block from 0x8000_0000 – 0x8007_FFFF.
To access 2 MB of address space starting at location 0x8000_0000, FB_CS1 must begin at the next byte
after FB_CS0 for a 1 MB address space. Therefore, CSAR0[BA] equals 0x8000, CSMR0[BAM] equals
0x000F, CSAR1[BA] equals 0x8010, and CSMR1[BAM] equals 0x000F. Then, FB_CS0 addresses one 1
MB memory block from 0x8000_0000 – 0x800F_FFFF. FB_CS1 addresses one 1MB memory block from
0x8010_0000 – 0x801F_FFFF.
0
1
This read-only bitfield is reserved and always has the value zero.
Write protect
Controls write accesses to the address range in the corresponding CSAR. Attempting to write to the range
of addresses for which CSARn[WP] is set results in a bus error termination of the internal cycle and no
external cycle.
0
1
This read-only bitfield is reserved and always has the value zero.
Valid
Indicates whether the corresponding CSAR, CSMR, and CSCR contents are valid. Programmed chip-
selects do not assert until V bit is set. Reset clears each CSMRn[V].
27
0
Corresponding address bit is used in chip-select decode
Corresponding address bit is a don’t care in chip-select decode.
Read and write accesses are allowed
Only read accesses are allowed
26
0
25
0
24
BAM
0
MCF51JF128 Reference Manual, Rev. 2, 03/2011
23
0
22
0
FB_CSMRn field descriptions
21
0
Table continues on the next page...
20
0
19
n
0
; n = (number of bits set in respective CSMR[BAM]) + 16.
18
0
Preliminary
17
0
16
0
15
0
Description
14
0
13
0
12
0
0
11
0
10
0
0
9
0
8
Freescale Semiconductor, Inc.
0
7
0
6
0
5
4
0
0
0
3
0
2
0
1
0
0