6-21
CHIP-SELECT UNIT
Example 6-1. Initializing the Chip-Select Unit (Continued)
DRAM_BASE
EQU
256
;window start address in Kbytes
DRAM_SIZE
EQU
256
;window size in Kbytes
DRAM_WAIT
EQU
0
;wait states
DRAM_RDY
EQU
INTRDY
;ignore bus ready
;The MPCS register is used to program both the MCS and PCS chip-selects.
;Below are the equates for the I/O peripherals (also used to program the PACS
;register.
IO_WAIT
EQU
4
;IO wait states
IO_RDY
EQU
INTRDY
;ignore bus ready
PCS_SPACE
EQU
IO
;put PCS# chip-selects in I/O space
PCS_FUNC
EQU
ALLPCS
;generate PCS5# and PCS6#
;The MMCS and MPCS register values are calculated using the above system
;constraints and the equations below:
MMCS_VAL
EQU
(DRAM_BASE SHL 6) OR (001F8H) OR (DRAM_RDY) OR (DRAM_WAIT)
MPCS_VAL
EQU
(DRAM_SIZE SHL 5) OR (08038H) OR (PCS_SPACE) OR (PCS_FUNC) OR
&
(IO_RDY) OR (IO_WAIT)
;I/O is selected using the PCS0# chip-select. Wait states assume operation at
;16 MHz. For this example, the Floppy Disk Controller is connected to PCS2# and
;PCS1# provides the DACK signal.
IO_BASE
EQU
1
;I/O start address in Kbytes
;The PACS register value is calculated using the above system constraints and
;the equation below.
PACS_VAL
EQU
(IO_BASE SHL 6) OR (0038H) OR (IO_RDY) OR (IO_WAIT)
;The following statements define the default assumptions for segment locations.
ASSUME
CS:CODE
ASSUME
DS:DATA
ASSUME
SS:DATA
ASSUME
ES:DATA
CODE
SEGMENT PUBLIC 'CODE'
;
;Entry point on power-up
;
FW_START
LABEL
FAR
;forces far jump
CLI
;disable interrupts
;Place register initialization code here
;
;Set up chip-selects.
;UCS - EPROM Select
(initialized during POWER_ON code)
;LCS - SRAM Select
(set to SRAM size)
;PCS - I/O Select
(PCS1:0 to support floppy)
;MCS - DRAM Select
(set to DRAM size)
mov
dx, LMCS_REG
;set up LMCS register
mov
ax, LMCS_VAL
out
dx, al
;remember that byte writes are OK
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: ......