7-13
REFRESH CONTROL UNIT
Figure 7-9. Regaining Bus Control to Run a DRAM Refresh Bus Cycle
HLDA
CLKOUT
HOLD
NOTES:
1. HLDA is deasserted; signaling need to run DRAM refresh cycles less than T
CLHAV
.
2. External bus master terminates use of the bus.
3. HOLD deasserted; greater than THVCL.
4. Hold may be reasserted after one clock.
5. Lines come out of float in order to run DRAM refresh cycle.
1
4
3
AD15:0
DEN
RD, WR,
BHE, S2:0
DT / R,
A19:16
6
5
2
T1
T1
T1
T1
T1
T4
T1
A1534-0A
Summary of Contents for 80C186XL
Page 1: ...80C186XL 80C188XL Microprocessor User s Manual...
Page 2: ...80C186XL 80C188XL Microprocessor User s Manual 1995...
Page 18: ...1 Introduction...
Page 19: ......
Page 27: ......
Page 28: ...2 Overview of the 80C186 Family Architecture...
Page 29: ......
Page 79: ......
Page 80: ...3 Bus Interface Unit...
Page 81: ......
Page 127: ......
Page 128: ...4 Peripheral Control Block...
Page 129: ......
Page 137: ......
Page 138: ...5 ClockGenerationand Power Management...
Page 139: ......
Page 154: ...6 Chip Select Unit...
Page 155: ......
Page 178: ...7 Refresh Control Unit...
Page 179: ......
Page 193: ......
Page 194: ...8 Interrupt Control Unit...
Page 195: ......
Page 227: ......
Page 228: ...9 Timer Counter Unit...
Page 229: ......
Page 253: ......
Page 254: ...10 Direct Memory Access Unit...
Page 255: ......
Page 283: ......
Page 284: ...11 Math Coprocessing...
Page 285: ......
Page 302: ...12 ONCE Mode...
Page 303: ......
Page 306: ...A 80C186 Instruction Set Additions and Extensions...
Page 307: ......
Page 318: ...B Input Synchronization...
Page 319: ......
Page 322: ...C Instruction Set Descriptions...
Page 323: ......
Page 371: ......
Page 372: ...D Instruction Set Opcodes and Clock Cycles...
Page 373: ......
Page 396: ...Index...
Page 397: ......