6-7
CHIP-SELECT UNIT
Figure 6-5. UMCS Register Definition
Register Name:
UCS Control Register
Register Mnemonic:
UMCS
Register Function:
Controls the operation of the UCS chip-select.
Bit
Mnemonic
Bit Name
Reset
State
Function
U17:10
Start
Address
0FFH
Defines the starting address for the chip-select.
During memory bus cycles, U17:10 are
compared with the A17:10 address bits. An
equal to or greater than result enables the UCS
chip-select if A19:18 are both one. Table 6-2 on
page 6-12 lists the only valid programming
combinations.
R2
Bus Ready
Disable
0H
When R2 is clear, bus ready must be active to
complete a bus cycle. When R2 is set, R1:0
control the number of bus wait states and bus
ready is ignored.
R1:0
Wait State
Value
3H
R1:0 define the minimum number of wait states
inserted into the bus cycle.
NOTE: Reserved register bits are shown with gray shading. Reserved bits must be written
to a logic zero to ensure compatibility with future Intel products. Programming
U17:10 with values other than those shown in Table 6-2 on page 6-12 results in
unreliable chip-select operation. Reading this register (before writing it) enables
the chip-select; however, none of the programmable fields will be properly initial-
ized.
15
0
R
1
R
0
R
2
U
1
1
U
1
0
U
1
3
U
1
2
U
1
5
U
1
4
U
1
7
U
1
6
A1141-0A
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: ......