;$INCLUDE   (reg_c51.INC)
transmit_completed      BIT 20H.1; software flag
serial_data             DATA 08H
data_save               DATA 09H
data_example            DATA 0AH;
; SPI
SPCON                   DATA    0C3H
SPSTA                   DATA    0C4H
SPDAT                   DATA    0C5H
; WATCHDOG TIMER
IEN1                    DATA    0B1H

ORG 0000h
    JMP SET_INTERRUPT

ORG 4Bh                 ; Endereço da interrupção SPI
    LJMP it_SPI         ; Programa para onde vai a rotina de interrupção

ORG 0100h

SET_INTERRUPT:
    MOV data_example,#55h;           /* data example */

    ORL SPCON,#10h;                  /* Master mode */
    SETB P1.1;                       /* enable master */
    ORL SPCON,#82h;                  /* Fclk Periph/128 */
    ANL SPCON,#0F7h;                 /* CPOL=0; transmit mode example */
    ORL SPCON,#04h;                  /* CPHA=1; transmit mode example */
    ORL IEN1,#04h;                   /* enable spi interrupt */
    ORL SPCON,#20h                  ; DESABILITA SS
    ORL SPCON,#40h;                  /* run spi */
    CLR transmit_completed;          /* clear software transfert flag */
    SETB EA;                         /* enable interrupts */

BEGIN:
    MOV P2, #0xFF                       ; Inicializa a porta P2

    MOV A, #0xFE
    MOV P2, A
    NOP
    MOV A, P2
    CJNE A, #0xFE, LINHA4

    MOV A, #0xFD
    MOV P2, A
    NOP
    MOV A, P2
    CJNE A, #0xFD, LINHA3

    MOV A, #0xFB
    MOV P2, A
    NOP
    MOV A, P2
    CJNE A, #0xFB, LINHA2

    MOV A, #0xF7
    MOV P2, A
    NOP
    MOV A, P2
    CJNE A, #0xF7, LINHA1

    JMP BEGIN

LINHA4:
    CALL DEBOUNCE
    JNB P2.7, ASTERICO
    JNB P2.6, ZERO
    JNB P2.5, HASH
    JNB P2.4, DDD
    JMP BEGIN
DDD:
    ;MOV A, #44h                            ; D ASCII
    JMP BEGIN
ZERO:
    ;MOV A, #30h                            ; 1 ASCII
    JMP BEGIN
HASH:
    ;MOV A, #23h                            ; # ASCII
    JMP BEGIN
ASTERICO:
    ;MOV A, #2Ah                            ; * ASCII
    LJMP TRANSMIT

LINHA3:
    CALL DEBOUNCE
    JNB P2.7, SETE
    JNB P2.6, OITO
    JNB P2.5, NOVE
    JNB P2.4, CCC
    JMP BEGIN
SETE:
    ;MOV A, #37h                            ; 7 ASCII
    MOV A, #07h
    JMP BEGIN
OITO:
    ;MOV A, #38h                            ; 8 ASCII
    MOV A, #08h
    JMP BEGIN
NOVE:
    ;MOV A, #39h                            ; 9 ASCII
    MOV A, #09h
    JMP BEGIN
CCC:
    ;MOV A, #43h                            ; C ASCII
    JMP BEGIN
LINHA2:
    CALL DEBOUNCE
    JNB P2.7, QUATRO
    JNB P2.6, CINCO
    JNB P2.5, SEIS
    JNB P2.4, BBB
    JMP BEGIN
QUATRO:
    ;MOV A, #34h                            ; 4 ASCII
    MOV A, #04h
    JMP BEGIN
CINCO:
    ;MOV A, #35h                            ; 5 ASCII
    MOV A, #05h
    JMP BEGIN
SEIS:
    ;MOV A, #36h                            ; 6 ASCII
    MOV A, #06h
    JMP BEGIN
BBB:
    ;MOV A, #42h                            ; B ASCII
    JMP BEGIN
LINHA1:
    CALL DEBOUNCE
    JNB P2.7, UM
    JNB P2.6, DOIS
    JNB P2.5, TRES
    JNB P2.4, AAA
    JMP BEGIN
UM:
    ;MOV A, #31h                            ; 1 ASCII
    MOV A, #01h
    JMP BEGIN
DOIS:
    ;MOV A, #32h                            ; 2 ASCII
    MOV A, #02h
    JMP BEGIN
TRES:
    ;MOV A, #33h                            ; 3 ASCII
    MOV A, #03h
    JMP BEGIN
AAA:
    ;MOV A, #41h                            ; A ASCII
    JMP BEGIN

CALC_FREQ:


TRANSMIT:
    MOV R0, #06h
    MOV SPDAT, R0
    JNB transmit_completed,$;     /* wait end of transmition */
    CLR transmit_completed;       /* clear software transfert flag */

    MOV SPDAT,#00h;               /* data is send to generate SCK signal */
    JNB transmit_completed,$;     /* wait end of transmition */
    CLR transmit_completed;       /* clear software transfert flag */
    MOV data_save,serial_data;    /* save receive data */
    JMP BEGIN

MINI_DELAY:
    MOV R3, #0FFH
    DJNZ R3, $
    RET

DEBOUNCE:
    CALL DELAY
    MOV R1, #250            ; VARIAVEL DE CONTROLE PARA 20 LEITURAS SUCESSIVAS
LOOPDEBOUNCE:
    MOV A, P2               ; MOVE O BYTE LIDO NO P2 PARA O ACUMULADOR P/ COMPARAÇÃO
    NOP
    CJNE A, P2, DEBOUNCEFAIL
    ;CALL MINI_DELAY
    DJNZ R1, LOOPDEBOUNCE   ; CASO A LEITURA SEJA CONFIRMADA, PARTE PARA AS LEITURAS SUCESSIVAS RESTANTES
    RET                     ; CASO FIM DE DEBOUNCE COM SUCESSO, RETORNA PARA VALIDAR A TECLA
DEBOUNCEFAIL:
    JMP BEGIN           ;

DELAY:
    MOV R3, #2                              ; CARREGA O REGISTRO DE CONTROLE DE TEMPO PARA APROXIMADAMENTE 200MS
LOOP3:
    MOV R4, #0FFH                           ; CARREGA O VALOR MAXIMO EM R4
LOOP4:
    MOV R2, #0FFH                           ; CARREGA O VALOR MAXIMO EM R2
    DJNZ R2, $                              ; DECREMENTA R2 PARA GASTAR TEMPO
    DJNZ R4, LOOP4                          ; DECREMENTA R4 APÓS 255 DECREMENTOS DE R2 PARA GASTAR TEMPO
    DJNZ R3, LOOP3                          ; DECREMENTA R3 APÓS 255 DECREMENTOS DE R4 PARA GASTAR TEMPO
    RET

;/**
; * FUNCTION_PURPOSE:interrupt
; * FUNCTION_INPUTS: void
; * FUNCTION_OUTPUTS: transmit_complete is software transfert flag
; */

it_SPI:;                         /* interrupt address is 0x004B */

    MOV R7,SPSTA;
    MOV ACC,R7
    JNB ACC.7,break1;case 0x80:
    MOV serial_data,SPDAT;       /* read receive data */
    SETB transmit_completed;     /* set software flag */
break1:

JNB ACC.4,break2;case 0x10:
;         /* put here for mode fault tasking */
break2:;

JNB ACC.6,break3;case 0x40:
;         /* put here for overrun tasking */
break3:;

RETI
END