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 80C186EA
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Страница 2: ...80C186EA 80C188EA Microprocessor User s Manual 1995...
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Страница 20: ...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 130: ...4 Peripheral Control Block...
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Страница 140: ...5 ClockGenerationand Power Management...
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Страница 166: ...6 Chip Select Unit...
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Страница 190: ...7 Refresh Control Unit...
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Страница 206: ...8 Interrupt Control Unit...
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Страница 239: ...INTERRUPT CONTROL UNIT 8 32...
Страница 240: ...9 Timer Counter Unit...
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Страница 266: ...10 Direct Memory Access Unit...
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Страница 296: ...11 Math Coprocessing...
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Страница 314: ...12 ONCE Mode...
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Страница 318: ...A 80C186 Instruction Set Additions and Extensions...
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Страница 330: ...B Input Synchronization...
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Страница 334: ...C Instruction Set Descriptions...
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Страница 383: ...INSTRUCTION SET DESCRIPTIONS C 48...
Страница 384: ...D Instruction Set Opcodes and Clock Cycles...
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Страница 408: ...Index...
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