CHIP-SELECT UNIT
6-18
6.5
CHIP-SELECTS AND BUS HOLD
The Chip-Select Unit decodes only internally generated address and bus state information. An ex-
ternal bus master cannot make use of the Chip-Select Unit. During HLDA, all chip-selects remain
inactive.
The circuit shown in Figure 6-12 allows an external bus master to access a device during bus
HOLD.
Figure 6-12. Using Chip-Selects During HOLD
6.6
EXAMPLES
The following sections provide examples of programming the Chip-Select Unit to meet the needs
of a particular application. The examples do not go into hardware analysis or design issues.
6.6.1
Example 1: Typical System Configuration
Figure 6-13 illustrates a block diagram of a typical system design with a 128 Kbyte EPROM and
a 32 Kbyte SRAM. The peripherals are mapped to I/O address space. Example 6.1 shows a pro-
gram template for initializing the Chip-Select Unit.
Device select
External Master Chip Select
CSU Chip Select
A1167-0A
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...
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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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