5-13
CLOCK GENERATION AND POWER MANAGEMENT
Figure 5-10. Entering Idle Mode
5.2.1.2 Bus Operation During Idle Mode
DMA requests, refresh requests and HOLD requests temporarily turn on the core clocks. If the
processor needs to run a DMA cycle during Idle mode, the internal core clock begins to toggle
on the falling CLKOUT edge three clocks after the processor samples the DMA request pin. After
one idle T-state, the processor runs the DMA cycle. The BIU uses the ready, wait state generation
and chip-select circuitry as necessary for DMA cycles during Idle mode. There is one idle T-state
after T4 before the internal core clock shuts off again.
Internal
Peripheral
Clock
CPU Core Clock
CLKOUT
S2:0
ALE
011
T4 or TI
T1
TI
TI
TI
Halt Cycle
A1119-0A
Summary of Contents for 80C186EA
Page 1: ...80C186EA 80C188EA Microprocessor User s Manual...
Page 2: ...80C186EA 80C188EA Microprocessor User s Manual 1995...
Page 19: ......
Page 20: ...1 Introduction...
Page 21: ......
Page 28: ...2 Overview of the 80C186 Family Architecture...
Page 29: ......
Page 79: ......
Page 80: ...3 Bus Interface Unit...
Page 81: ......
Page 129: ......
Page 130: ...4 Peripheral Control Block...
Page 131: ......
Page 139: ......
Page 140: ...5 ClockGenerationand Power Management...
Page 141: ......
Page 165: ......
Page 166: ...6 Chip Select Unit...
Page 167: ......
Page 190: ...7 Refresh Control Unit...
Page 191: ......
Page 205: ......
Page 206: ...8 Interrupt Control Unit...
Page 207: ......
Page 239: ...INTERRUPT CONTROL UNIT 8 32...
Page 240: ...9 Timer Counter Unit...
Page 241: ......
Page 265: ......
Page 266: ...10 Direct Memory Access Unit...
Page 267: ......
Page 295: ...DIRECT MEMORY ACCESS UNIT 10 28...
Page 296: ...11 Math Coprocessing...
Page 297: ......
Page 314: ...12 ONCE Mode...
Page 315: ......
Page 318: ...A 80C186 Instruction Set Additions and Extensions...
Page 319: ......
Page 330: ...B Input Synchronization...
Page 331: ......
Page 334: ...C Instruction Set Descriptions...
Page 335: ......
Page 383: ...INSTRUCTION SET DESCRIPTIONS C 48...
Page 384: ...D Instruction Set Opcodes and Clock Cycles...
Page 385: ......
Page 408: ...Index...
Page 409: ......