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20-7
20.3.2
Chip-Select Mask Registers (CSMR0 – CSMR5)
CSMR
n
registers specify the address mask and allowable access types for the respective chip-selects.
20.3.3
Chip-Select Control Registers (CSCR0 – CSCR5)
Each CSCR
n
controls the auto-acknowledge, address setup and hold times, port size, burst capability, and
number of wait states. To support the global chip-select, FB_CS0, the CSCR0 reset values differ from the
Address: 0xFC00_8004 (CSMR0)
0xFC00_8010 (CSMR1)
0xFC00_801C (CSMR2)
0xFC00_8028 (CSMR3)
0xFC00_8034 (CSMR4)
0xFC00_8040 (CSMR5)
Access: User read/write
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
R
BAM
0 0 0 0 0 0 0
WP
0 0 0 0 0 0 0
V
W
Reset 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0
0 0 0 0 0 0 0 0
Figure 20-2. Chip-Select Mask Registers (CSMR
n
)
Table 20-5. CSMR
n
Field Descriptions
Field
Description
31–16
BAM
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.
0 Corresponding address bit is used in chip-select decode.
1 Corresponding address bit is a don’t care in chip-select decode.
The block size for FB_CS
n
is 2
n
; n = (number of bits set in respective CSMR[BAM]) + 16.
For example, if CSAR0 equals 0x0000 and CSMR0[BAM] equals 0x0008, FB_CS0 addresses two discontinuous
64 KB memory blocks: one from 0x0_0000 – 0x0_FFFF and one from 0x8_0000 – 0x8_FFFF.
Likewise, for FB_CS0 to access 32 MB of address space starting at location 0x00_0000, FB_CS1 must begin at the
next byte after FB_CS0 for a 16 MB address space. Therefore, CSAR0 equals 0x0000,
CSMR0[BAM] equals 0x01FF, CSAR1 equals 0x0200, and CSMR1[BAM] equals 0x00FF.
15–9
Reserved, must be cleared.
8
WP
Write protect. Controls write accesses to the address range in the corresponding CSAR. Attempting to write to the
range of addresses for which CSAR
n
[WP] is set results in a bus error termination of the internal cycle and no external
cycle.
0 Read and write accesses are allowed
1 Only read accesses are allowed
7–1
Reserved, must be cleared.
0
V
Valid bit. Indicates whether the corresponding CSAR, CSMR, and CSCR contents are valid. Programmed
chip-selects do not assert until V bit is set (except for FB_CS0, which acts as the global chip-select). Reset clears
each CSMR
n
[V].
Note:
At reset, no chip-select other than FB_CS0 can be used until the CSMR0[V] is set. Afterward, FB_CS[5:0]
functions as programmed.
0 Chip-select invalid
1 Chip-select valid
Summary of Contents for MCF54455
Page 33: ...xxviii Freescale Semiconductor ...
Page 67: ...Freescale Semiconductor 1 ...
Page 125: ...Freescale Semiconductor 1 ...
Page 145: ...Enhanced Multiply Accumulate Unit EMAC 5 21 Freescale Semiconductor ...
Page 173: ...Cache 6 28 Freescale Semiconductor ...
Page 179: ...Static RAM SRAM 7 6 Freescale Semiconductor ...
Page 207: ...Power Management 9 16 Freescale Semiconductor ...
Page 323: ...Reset Controller Module 13 8 Freescale Semiconductor ...
Page 389: ...Pin Multiplexing and Control 16 44 Freescale Semiconductor ...
Page 575: ...PCI Bus Controller 22 58 Freescale Semiconductor ...
Page 600: ...Advanced Technology Attachment ATA Freescale Semiconductor 23 25 ...
Page 601: ...Freescale Semiconductor 1 ...
Page 842: ...I2 C Interface Freescale Semiconductor 33 16 ...
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Page 921: ...Revision History A 6 Freescale Semiconductor ...