3-19
BUS INTERFACE UNIT
Figure 3-18. Normally Ready System Timings
Conditions causing the BIU to become idle include the following.
•
The instruction prefetch queue is full.
•
An effective address calculation is in progress.
•
The bus cycle inherently requires idle states (e.g., interrupt acknowledge, locked opera-
tions).
•
Instruction execution forces idle states (e.g., HLT, WAIT).
ARDY
CLKOUT
In a Normally-Ready system, a wait state will be inserted when 1 & 2 are met.
(Assumes SRDY is low.)
T2
T3
TW
ARDY
CLKOUT
Alternatively, in a Normally-Ready system, a wait state will be inserted
when1 & 2 are met for SRDY and ARDY.
1. TARYCL, TSRYCL : ARDY and SRDY low to clock low
2. TCHARX, TCLSRY : ARDY and SRDY low from clock low
T2
T3
TW
1
2
1
2
!
Failure to meet ARDY and SRDY setup and hold can cause a device failure
(i.e., the bus hangs or operates inappropriately).
1. TARYCH : ARDY low to clock high
2. TARYCHL : Clock high to ARDY high (ARDY inactive hold time)
SRDY
T4
T4
A1512-0A
Содержание 80C186XL
Страница 1: ...80C186XL 80C188XL Microprocessor User s Manual...
Страница 2: ...80C186XL 80C188XL Microprocessor User s Manual 1995...
Страница 18: ...1 Introduction...
Страница 19: ......
Страница 27: ......
Страница 28: ...2 Overview of the 80C186 Family Architecture...
Страница 29: ......
Страница 79: ......
Страница 80: ...3 Bus Interface Unit...
Страница 81: ......
Страница 127: ......
Страница 128: ...4 Peripheral Control Block...
Страница 129: ......
Страница 137: ......
Страница 138: ...5 ClockGenerationand Power Management...
Страница 139: ......
Страница 154: ...6 Chip Select Unit...
Страница 155: ......
Страница 178: ...7 Refresh Control Unit...
Страница 179: ......
Страница 193: ......
Страница 194: ...8 Interrupt Control Unit...
Страница 195: ......
Страница 227: ......
Страница 228: ...9 Timer Counter Unit...
Страница 229: ......
Страница 253: ......
Страница 254: ...10 Direct Memory Access Unit...
Страница 255: ......
Страница 283: ......
Страница 284: ...11 Math Coprocessing...
Страница 285: ......
Страница 302: ...12 ONCE Mode...
Страница 303: ......
Страница 306: ...A 80C186 Instruction Set Additions and Extensions...
Страница 307: ......
Страница 318: ...B Input Synchronization...
Страница 319: ......
Страница 322: ...C Instruction Set Descriptions...
Страница 323: ......
Страница 371: ......
Страница 372: ...D Instruction Set Opcodes and Clock Cycles...
Страница 373: ......
Страница 396: ...Index...
Страница 397: ......