Created
November 19, 2011 02:33
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LCD HD44780 PIC
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| ; PORTC is connected to D4:D7 as C0:C3 | |
| ; PORTA is connected to RS/RW/E as A0/A1/A2 | |
| #include p16f690.inc | |
| PROCESSOR p16f690 | |
| __CONFIG _INTRC_OSC_NOCLKOUT&_FCMEN_ON&_IESO_ON&_BOR_ON&_CPD_OFF&_CP_OFF&_MCLRE_OFF&_PWRTE_OFF&_WDT_OFF | |
| RS EQU 5 | |
| RW EQU 1 | |
| E EQU 2 | |
| dcount EQU 0x20 | |
| dcount2 EQU 0x21 | |
| temp EQU 0x22 | |
| i EQU 0x23 | |
| ptr EQU 0x24 | |
| ORG 0x0 | |
| bsf STATUS,RP0 | |
| clrf TRISA | |
| clrf TRISC | |
| bcf STATUS,RP0 | |
| clrf ADCON0 ;no analog input | |
| call LCD_reset | |
| call LCD_init | |
| movlw 1 | |
| call LCD_set_ad | |
| call LCD_String | |
| goto $ | |
| Text1: | |
| addwf PCL,F | |
| dt b'10011101',"ALL N00BZ!!!",b'10011101',0 | |
| ;3n+1 cycles | |
| Delay: | |
| movwf dcount | |
| decfsz dcount,F | |
| goto $-1 | |
| return | |
| ;766*n cycles | |
| Delay_lng: | |
| movwf dcount2 | |
| movlw 0 | |
| Dl: call Delay ; 766 * dcount2 | |
| decfsz dcount2,F | |
| goto Dl | |
| return | |
| LCD_Shift_L: | |
| movlw 0x18 | |
| call LCD_Com | |
| movlw d'14' | |
| call Delay | |
| return | |
| LCD_Shift_R: | |
| movlw 0x1c | |
| call LCD_Com | |
| movlw d'14' | |
| call Delay | |
| return | |
| LCD_init: | |
| movlw 0x28 ;4-bits, DL | |
| call LCD_Com | |
| movlw d'14' ; t > 40 us. | |
| call Delay | |
| movlw 0x0c ;Display on, Blink, Underline | |
| call LCD_Com | |
| movlw d'14' | |
| call Delay | |
| call LCD_clr | |
| return | |
| LCD_reset: | |
| movlw d'40' | |
| call Delay_lng | |
| movlw 0x20 ; set to 4-bit | |
| call LCD_Com | |
| movlw d'34' | |
| call Delay | |
| return | |
| LCD_set_ad: | |
| iorlw 0x80 | |
| call LCD_Com | |
| return | |
| LCD_clr: | |
| movlw 0x01 ;Clear screen | |
| call LCD_Com | |
| movlw d'3' | |
| call Delay_lng | |
| return | |
| LCD_Command: | |
| movwf PORTC | |
| bcf PORTA,RS ; 0 for command | |
| bcf PORTA,RW ; 0 for write | |
| bsf PORTA,E | |
| bcf PORTA,E | |
| return | |
| ;high nibble first, low nibble later, 4-bit interface. | |
| LCD_Com: | |
| bcf PORTA,RS | |
| bcf PORTA,RW | |
| movwf temp | |
| swapf temp,W | |
| andlw 0x0f | |
| movwf PORTC | |
| bsf PORTA,E | |
| bcf PORTA,E | |
| movf temp,W | |
| andlw 0x0f | |
| movwf PORTC | |
| bsf PORTA,E | |
| bcf PORTA,E | |
| return | |
| LCD_Putc: | |
| bsf PORTA,RS | |
| bcf PORTA,RW | |
| movwf temp | |
| swapf temp,W | |
| andlw 0x0f | |
| movwf PORTC | |
| bsf PORTA,E | |
| bcf PORTA,E | |
| bsf PORTA,RS | |
| movf temp,W | |
| andlw 0x0f | |
| movwf PORTC | |
| bsf PORTA,E | |
| bcf PORTA,E | |
| return | |
| LCD_String: | |
| clrf i | |
| L: movf i,W | |
| call Text1 | |
| addlw 0 | |
| btfsc STATUS,Z | |
| return | |
| call LCD_Putc | |
| incf i,F | |
| movlw d'14' | |
| call Delay | |
| goto L | |
| ENDM |
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