3-33
BUS INTERFACE UNIT
Figure 3-28. Returning to HALT After a DMA Bus Cycle
3.5.6 Exiting HALT
In Powerdown mode, only an NMI forces the BIU to exit the HALT bus state. In any other power
management mode, either an NMI or any unmasked INTn interrupt causes the BIU to exit HALT.
The first bus operations to occur after exiting HALT are read cycles to reload the CS:IP registers.
Figure 3-29 and Figure 3-30 show how the HALT bus state is exited when an NMI or INTn oc-
curs.
T1
T2
T3
T4
T1
T2
T3
TI
CLKOUT
AD15:0
[AD7:0]
TI
TI
ALE
[A15:8]
A19:16
Valid Status
Valid Status
Note
Addr
8H
8H
Note
Valid
Valid
NOTE: Drives previous bus cycle value
TI
BHE
[RFSH=1]
S2:0
T4
Address
Note
Address
Addr
Addr
Valid Data
Addr
A1052-0A
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: ......
Страница 265: ......
Страница 266: ...10 Direct Memory Access Unit...
Страница 267: ......
Страница 295: ...DIRECT MEMORY ACCESS UNIT 10 28...
Страница 296: ...11 Math Coprocessing...
Страница 297: ......
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: ......