3-29
BUS INTERFACE UNIT
Figure 3-25. HALT Bus Cycle
Table 3-6. HALT Bus Cycle Pin States
Pin(s)
Pin State
AD15:0 (AD7:0 for 8-bit)
Float
A15:8 (8-bit)
Drive Address
A19:16
Drive 8H or Zero
BHE (16-bit)
Drive Last Value
RD, WR, DEN, DT/R, RFSH (8-bit), S2:0
Drive One
011
CLKOUT
ALE
S2:0
AD15:0
[AD7:0]
[A15:8]
A19:16
NOTES:
1. The AD15:0 [AD7:0] bus can be floating, driving a previous write data value,
or driving the next instruction prefetch address value. For an 8-bit device,
A15:8 drives either the previous bus address value or the next instruction
prefetch address value.
2. The A19:16 bus drives either zero (all low) or 8H (all low except A19/S6,
which can be high if the previous bus cycle was a DMA or refresh operation).
T1
TI
TI
BHE
[RFSH = 1]
Note 1
Note 1
Note 2
A1513-0A
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: ......