AN1447 Datasheet, PDF (24/26 Pages) STMicroelectronics – SOFTWARE DRIVER FOR 4-MULTIPLEXED LCD WITH A STANDARD ST62

4-MULTIPLEXED LCD WITH A STANDARD ST62
add
ld
ld
andi
add
ld
a,LCD_Ph
x,a
a,OR_com
a,COM_MASK
a,(x)
OR_com2,a
;--- Perform the changes on the real ports ---
; Segments port
ld a,DR_seg_2
ld DR_seg,a
; Commons port
ld a,OR_com
andi a,COM_MASK
ld OR_com,a
ld a,DDR_com2
ld DDR_com,a
ld a,DR_com_2
ld DR_com,a
ld a,OR_com2
ld OR_com,a
;--- Increment phase counter ---
inc
ld
andi
ld
LCD_Ph
a,LCD_Ph
a,07h
LCD_Ph,a
; LCD_Ph = (LCD_Ph + 1) mod 8
; Output internal to the driver:
; ’LCD_Ph’ updated
ret
;*****************************************************************
find_seg:
; Finds the segment outputs for a given digit, a given
; character and a given LCD phase.
; Prereq. : none
; Inputs : ’LCD_Ph’, V = LCD_Ph mod 4,
;
a = code of the character (0 to 15),
;
W = segment I/O port mask for the digit
; Outputs : ’DR_seg_2’ refreshed
; Modifies : X
;*****************************************************************
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