80C186EC/80C188EC Microprocessor User's Manual

CHIP-SELECT UNIT
;SET UP CHIP SELECTS
; UCS# - EPROM Select
; LCS# - SRAM Select
; GCS1# - DRAM Select
; GCS2# - FLOPPY Select
; GCS0# - DACK Generator (programmed during DMA init)
MOV DX, UCSSP ;Finish setting up UCS#
MOV AX, UCSSP_VAL
OUT DX, AL ;Remember, byte writes work ok
MOV DX, LCSST ;Set up LCS#
MOV AX, LCSST_VAL
OUT DX, AL
MOV DX, LCSSP
MOV AX, LCSSP_VAL
OUT DX, AL ;Remember, byte writes work ok
MOV DX, GCS1ST ;Set up GCS1#
MOV AX, GCS1ST_VAL
OUT DX, AL
MOV AX, GCS1SP_VAL
MOV DX, GCS1SP
OUT DX, AL ;Remember, byte writes work ok
MOV DX, GCS2ST ;Set up GCS2#
MOV AX, GCS2ST_VAL
OUT DX, AL
MOV DX, GCS2SP
MOV AX, GCS2SP_VAL
OUT DX, AL ;Remember, byte writes work ok
;Place remaining User Code here.
CODE
ENDS
;POWER ON RESET CODE TO GET STARTED
ASSUME CS:POWER_ON
POWER_ONSEGMENT AT 0FFFFH
MOV DX, UCSST ;Point to UCS register
MOV AX, UCSST_VAL ;Reprogram UCS# for EPROM size
OUT DX, AL
JMP FW_START ;Jump to start of init code
POWER_ON ENDS
Example 6-1. Initializing the Chip-Select Unit (Continued)
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