CHIP-SELECT UNIT
6-6
6.4
PROGRAMMING
Four registers determine the operating characteristics of the chip-selects. The Peripheral Control
Block defines the location of the Chip-Select Unit registers. Table 6-1 lists the registers and their
associated programming names.
The control registers (Figures 6-5 through 6-7) define the base address and bus ready and wait
state requirements for the corresponding chip-selects. The alternate control register (Figure 6-9)
defines the block size for MCS3:0. It also selects memory or I/O space for PCS6:0, selects the
function of the PCS6:5 pins, and defines the bus ready and wait state requirements for PCS6:4.
6.4.1
Initialization Sequence
Chip-selects do not have to be initialized in any specific order. However, the following guidelines
help prevent a system failure.
1.
Initialize local memory chip-selects
2.
Initialize local peripheral chip-selects
3.
Perform local diagnostics
4.
Initialize off-board memory and peripheral chip-selects
5.
Complete system diagnostics
An unmasked interrupt or NMI must not occur until the interrupt vector addresses have been writ-
ten to memory. Failure to prevent an interrupt from occurring during initialization will cause a
system failure. Use external logic to generate the chip-select if interrupts cannot be masked prior
to initialization.
Table 6-1. Chip-Select Unit Registers
Control Register
Mnemonic
Alternate Register
Mnemonic
Chip-Select Affected
UMCS
None
UCS
LMCS
None
LCS
MMCS
MPCS
MCS3:0
PACS
MPCS
PCS6:0
Содержание 80C186XL
Страница 1: ...80C186XL 80C188XL Microprocessor User s Manual...
Страница 2: ...80C186XL 80C188XL Microprocessor User s Manual 1995...
Страница 18: ...1 Introduction...
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Страница 28: ...2 Overview of the 80C186 Family Architecture...
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Страница 80: ...3 Bus Interface Unit...
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Страница 128: ...4 Peripheral Control Block...
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Страница 138: ...5 ClockGenerationand Power Management...
Страница 139: ......
Страница 154: ...6 Chip Select Unit...
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Страница 178: ...7 Refresh Control Unit...
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Страница 194: ...8 Interrupt Control Unit...
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Страница 228: ...9 Timer Counter Unit...
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Страница 254: ...10 Direct Memory Access Unit...
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Страница 284: ...11 Math Coprocessing...
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Страница 302: ...12 ONCE Mode...
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Страница 306: ...A 80C186 Instruction Set Additions and Extensions...
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Страница 318: ...B Input Synchronization...
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Страница 322: ...C Instruction Set Descriptions...
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Страница 372: ...D Instruction Set Opcodes and Clock Cycles...
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Страница 396: ...Index...
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