M68HC11K Datasheet, PDF (244/290 Pages) Freescale Semiconductor, Inc – HCMOS Microcontroller Unit

Freescale Semiconductor, Inc.
Memory Expansion and Chip Selects
11.4.3.3 General-Purpose Chip Select 1 Control Register
Address: $005D
Bit 7
6
5
4
3
2
1
Read:
G1DG2 G1DPC G1POL
Write:
G1AV
G1SZA G1SZB G1SCC
Reset: 0
0
0
0
0
0
0
Figure 11-9. General-Purpose Chip Select 1
Control Register (GPCS1C)
Bit 0
G1SZD
0
G1POL — General-Purpose Chip Select 1 Polarity Select Bit
0 = CSGP1 active low
1 = CSGP1 active high
G1AV — General-Purpose Chip Select 1 Address Valid Select Bit
0 = CSGP1 is valid during E high time.
1 = CSGP1 is valid during address valid time.
G1SZ[A:D] — General-Purpose Chip Select 1 Size Bits
They select the range of GPCS1. Refer to Table 11-6.
Table 11-6. General-Purpose Chip Select 1 Size Control
G1SZ[A:D]
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100–1111
Size (Bytes)
Disabled
2K
4K
8K
16 K
32 K
64 K
128 K
256 K
512 K
Follow window 1
Follow window 2
Default to 512 K
Valid Bits
(MXGS1 = 0)
None
G1A[15:11]
G1A[15:11]
G1A[15:13]
G1A[15:14]
G1A[15]
None
None
None
None
None
None
None
Valid Bits
(MXGS1 = 1)
None
G1A[18:11]
G1A[18:12]
G1A[18:13]
G1A[18:14]
G1A[18:15]
G1A[18:16]
G1A[18:17]
G1A18
None
None
None
None
Technical Data
244
Memory Expansion and Chip Selects
For More Information On This Product,
Go to: www.freescale.com
M68HC11K Family
MOTOROLA