Direct LCD Drive

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BOUCLE2

LDI

TCR,18

; timer initialization

LDI

TSCR,7Fh

; program it at 1.5 ms

INC

TABU

; determine data/rom window address

INC

TABD

; of tables 1 & 2 for phase 2

CALL DATALCD

; determine segments driver byte for PHASE 2

LDI

ORA,07h

; BP1 = Vdd/2 ; BP2 = Vss therefore

LDI

DRA,40h

LDI

DDRA,87h

; A6 becomes high impedance input

LDI

ORA,87h

; & A7 becomes push pull output at Vss

LD

DRB,A

; load segments driver byte on port

WAIT

;**************************************************************************

BOUCLE3

LDI

TCR,18

; timer initialization

LDI

TSCR,7Fh

; program it at 1.5 ms

INC

TABU

; determine data/rom window address

INC

TABD

; of tables 1 & 2 for phase 2

CALL DATALCD

; determine segments driver byte for PHASE 3

LDI

DRA,0C0h

; BP1 = Vdd/2 ; BP2 = Vdd therefore

; A6 remains high impedance input

; A7 becomes push pull output at Vdd

LD

DRB,A

; load segments driver byte on port

WAIT

;**************************************************************************

BOUCLE4

LDI

TCR,18

; timer initialization

LDI

TSCR,7Fh

; program it at 1.5 ms

INC

TABU

; determine data/rom window address

INC

TABD

; of tables 1 & 2 for phase 2

CALL DATALCD

; determine segments driver byte for PHASE 4

LDI

ORA,07h

; BP1 = Vss ; BP2 =A Vdd/2 therefore

LDI

DRA,80h

LDI

DDRA,47h

; A6 becomes output at Vss

LDI

ORA,47h

; A7 becomes high impedance input

LD

DRB,A

; load segments driver byte on port

WAIT

;**************************************************************************

FINBOUCLE JRR

0,FLAGS,BOUCLE1 ;IF ON/OFF button remains pushed,

; THEN circuit is in stand by & display is

; ELSE continue digits display

LDI

DRA,00h

LDI

DDRA,0C7h

LDI

ORA,0C7h

; BP1 & BP2 on output to Vss

LDI

DRB,00h

PREPSOMM CALL CLAVIER

; test of keyboard

LD

A,TOUCH

CPI

A,0Ah

; wait falling edge of ON/OFF button

JRZ PREPSOMM

; before stop display mode

JP

SOMMEIL

;**************************************************************************

;*

END OF MAIN PROGRAM

;**************************************************************************

ANNEX 1: Software of the ST6215x based application (Continued)