mc68hc711k4 Freescale Semiconductor, Inc, mc68hc711k4 Datasheet - Page 240

• Manufacturer Part Number: mc68hc711k4
• Description: Hcmos Microcontroller Unit
• Manufacturer: Freescale Semiconductor, Inc

Memory Expansion and Chip Selects
11.4.1 Program Chip Select
Technical Data
240
Address: $005B
The program chip select signal accesses external memory in the main
program area within the MCU’s 64-Kbyte memory map. Program chip
select validity is fixed at address valid timing and polarity is fixed at active
low. The chip-select control register (CSCTL) contains bits to enable
CSPROG, determine its priority over the general-purpose chip selects,
and set its effective address range. Clock stretching can be set from zero
to three cycles.
GCSPR — General-Purpose Chip Select Priority Bit
PCSEN — Program Chip Select Enable Bit
PCSZA and PCSZB — Program Chip Select Size A Bit and Program
Reset:
Read:
Write:
These bits determine the address range of CSPROG, as shown in
Table
Freescale Semiconductor, Inc.
For More Information On This Product,
0 = Program chip select has priority over general-purpose chip
1 = General-purpose chip selects have priority over program chip
0 = CSPROG disabled and port H bit 7 available as GPIO
1 = CSPROG enabled out of reset and uses port H bit 7 pin
Figure 11-5. Chip-Select Control Register (CSCTL)
IOEN
Memory Expansion and Chip Selects
Bit 7
11-5.
selects
select
0
PCSZA
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0
0
1
1
Table 11-5. Program Chip Select Size
IOPL
6
0
PCSZB
0
1
0
1
Chip Select Size B Bit
IOCSA
5
0
Size (Bytes)
IOSZ
64 K
32 K
16 K
8 K
4
0
GCSPR
3
0
Address Range
$C000–$FFFF
$E000–$FFFF
$0000–$FFFF
$8000–$FFFF
PCSEN
2
1
M68HC11K Family
PCSZA
1
0
MOTOROLA
PCSZB
Bit 0
0