BUS INTERFACE UNIT
3-46
Figure 3-38. Exiting HOLD
3.8 BUS CYCLE PRIORITIES
The BIU arbitrates requests for bus cycles from the Execution Unit, the integrated peripherals
(e.g., Interrupt Control Unit) and external bus masters (i.e., bus hold requests). The list below
summarizes the priorities for all bus cycle requests (from highest to lowest).
1. Instruction execution read/write following a non-pipelined effective address calculation.
2. Refresh bus cycles.
3. Bus hold request.
4. Single step interrupt vectoring sequence.
5. Non-Maskable interrupt vectoring sequence.
HLDA
CLKOUT
HOLD
1
4
3
AD15:0
DEN
RD, WR, BHE,
DT / R, S2:0,
A19:16
5
2
NOTES:
1.
2.
3.
4.
5.
T
T
T
T
CLIS
CLOV
CHOV
CLOV
: HOLD recognition setup to clock low
: HOLD internally synchronized
: Clock low to HLDA low
: Clock high to signal active (high or low)
: Clock low to signal active (high or low)
A1099-0A
Содержание 80C186EA
Страница 1: ...80C186EA 80C188EA Microprocessor User s Manual...
Страница 2: ...80C186EA 80C188EA Microprocessor User s Manual 1995...
Страница 19: ......
Страница 20: ...1 Introduction...
Страница 21: ......
Страница 28: ...2 Overview of the 80C186 Family Architecture...
Страница 29: ......
Страница 79: ......
Страница 80: ...3 Bus Interface Unit...
Страница 81: ......
Страница 129: ......
Страница 130: ...4 Peripheral Control Block...
Страница 131: ......
Страница 139: ......
Страница 140: ...5 ClockGenerationand Power Management...
Страница 141: ......
Страница 165: ......
Страница 166: ...6 Chip Select Unit...
Страница 167: ......
Страница 190: ...7 Refresh Control Unit...
Страница 191: ......
Страница 205: ......
Страница 206: ...8 Interrupt Control Unit...
Страница 207: ......
Страница 239: ...INTERRUPT CONTROL UNIT 8 32...
Страница 240: ...9 Timer Counter Unit...
Страница 241: ......
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Страница 266: ...10 Direct Memory Access Unit...
Страница 267: ......
Страница 295: ...DIRECT MEMORY ACCESS UNIT 10 28...
Страница 296: ...11 Math Coprocessing...
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Страница 314: ...12 ONCE Mode...
Страница 315: ......
Страница 318: ...A 80C186 Instruction Set Additions and Extensions...
Страница 319: ......
Страница 330: ...B Input Synchronization...
Страница 331: ......
Страница 334: ...C Instruction Set Descriptions...
Страница 335: ......
Страница 383: ...INSTRUCTION SET DESCRIPTIONS C 48...
Страница 384: ...D Instruction Set Opcodes and Clock Cycles...
Страница 385: ......
Страница 408: ...Index...
Страница 409: ......