217 lines
5.3 KiB
NASM
217 lines
5.3 KiB
NASM
;------------------------------------------------------------------------------
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; HD44780 LCD Assembly driver
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; http://avr-mcu.dxp.pl
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; e-mail : radek@dxp.pl
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; (c) Radoslaw Kwiecien
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;------------------------------------------------------------------------------
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.include "tn2313def.inc"
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.include "hd44780.inc"
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.equ LCD_PORT = PORTB
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.equ LCD_DDR = DDRB
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.equ LCD_PIN = PINB
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.equ LCD_D4 = 0
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.equ LCD_D5 = 1
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.equ LCD_D6 = 2
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.equ LCD_D7 = 3
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.equ LCD_RS = 4
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.equ LCD_EN = 6
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;------------------------------------------------------------------------------
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; Data segment
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;------------------------------------------------------------------------------
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.dseg
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;------------------------------------------------------------------------------
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; Code segment
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;------------------------------------------------------------------------------
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.cseg
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#include "div8u.asm"
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;------------------------------------------------------------------------------
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; Write half byte to LCD
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;------------------------------------------------------------------------------
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LCD_WriteNibble:
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sbi LCD_PORT, LCD_EN
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sbrs r16, 0
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cbi LCD_PORT, LCD_D4
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sbrc r16, 0
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sbi LCD_PORT, LCD_D4
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sbrs r16, 1
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cbi LCD_PORT, LCD_D5
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sbrc r16, 1
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sbi LCD_PORT, LCD_D5
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sbrs r16, 2
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cbi LCD_PORT, LCD_D6
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sbrc r16, 2
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sbi LCD_PORT, LCD_D6
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sbrs r16, 3
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cbi LCD_PORT, LCD_D7
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sbrc r16, 3
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sbi LCD_PORT, LCD_D7
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cbi LCD_PORT, LCD_EN
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ret
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;------------------------------------------------------------------------------
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; Write data byte to LCD
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;------------------------------------------------------------------------------
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LCD_WriteData:
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sbi LCD_PORT, LCD_RS
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push r16
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swap r16
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rcall LCD_WriteNibble
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pop r16
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rcall LCD_WriteNibble
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clr XH
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ldi XL,250
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rcall Wait4xCycles
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ret
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;------------------------------------------------------------------------------
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; Write command byte to LCD
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;------------------------------------------------------------------------------
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LCD_WriteCommand:
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cbi LCD_PORT, LCD_RS
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push r16
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swap r16
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rcall LCD_WriteNibble
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pop r16
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rcall LCD_WriteNibble
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ldi r16,2
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rcall WaitMiliseconds
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ret
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;------------------------------------------------------------------------------
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; Write string (from program memory)
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;------------------------------------------------------------------------------
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LCD_WriteString:
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lpm r16, Z+
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cpi r16, 0
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breq exit
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rcall LCD_WriteData
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rjmp LCD_WriteString
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exit:
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ret
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;------------------------------------------------------------------------------
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; Display one digit in HEX code
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;------------------------------------------------------------------------------
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LCD_WriteHexDigit:
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cpi r16,10
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brlo Num
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ldi r17,'7'
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add r16,r17
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rcall LCD_WriteData
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ret
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Num:
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ldi r17,'0'
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add r16,r17
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rcall LCD_WriteData
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ret
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;------------------------------------------------------------------------------
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; Display 8-byte hex value of r16
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;------------------------------------------------------------------------------
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LCD_WriteHex8:
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push r17
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push r16
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swap r16
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andi r16,0x0F
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rcall LCD_WriteHexDigit
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pop r16
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andi r16,0x0F
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rcall LCD_WriteHexDigit
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pop r17
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ret
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;------------------------------------------------------------------------------
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; Display decimal value of r16
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;------------------------------------------------------------------------------
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LCD_WriteDecimal:
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clr r14
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LCD_WriteDecimalLoop:
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ldi r17,10
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rcall div8u
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inc r14
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push r15
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cpi r16,0
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brne LCD_WriteDecimalLoop
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LCD_WriteDecimalLoop2:
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ldi r17,'0'
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pop r16
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add r16,r17
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rcall LCD_WriteData
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dec r14
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brne LCD_WriteDecimalLoop2
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ret
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;------------------------------------------------------------------------------
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; Set address in Display Data RAM
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;------------------------------------------------------------------------------
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LCD_SetAddressDD:
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ori r16, HD44780_DDRAM_SET
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rcall LCD_WriteCommand
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ret
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;------------------------------------------------------------------------------
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; Set address in Character Generator RAM
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;------------------------------------------------------------------------------
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LCD_SetAddressCG:
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ori r16, HD44780_CGRAM_SET
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rcall LCD_WriteCommand
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ret
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;------------------------------------------------------------------------------
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; Initialization of LCD
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;------------------------------------------------------------------------------
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LCD_Init:
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sbi LCD_DDR, LCD_D4
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sbi LCD_DDR, LCD_D5
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sbi LCD_DDR, LCD_D6
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sbi LCD_DDR, LCD_D7
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sbi LCD_DDR, LCD_RS
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sbi LCD_DDR, LCD_EN
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cbi LCD_PORT, LCD_RS
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cbi LCD_PORT, LCD_EN
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ldi r16, 100
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rcall WaitMiliseconds
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ldi r17, 3
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InitLoop:
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ldi r16, 0x03
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rcall LCD_WriteNibble
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ldi r16, 5
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rcall WaitMiliseconds
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dec r17
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brne InitLoop
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ldi r16, 0x02
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rcall LCD_WriteNibble
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ldi r16, 1
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rcall WaitMiliseconds
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ldi r16, HD44780_FUNCTION_SET | HD44780_FONT5x7 | HD44780_TWO_LINE | HD44780_4_BIT
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rcall LCD_WriteCommand
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ldi r16, HD44780_DISPLAY_ONOFF | HD44780_DISPLAY_OFF
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rcall LCD_WriteCommand
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ldi r16, HD44780_CLEAR
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rcall LCD_WriteCommand
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ldi r16, HD44780_ENTRY_MODE |HD44780_EM_SHIFT_CURSOR | HD44780_EM_INCREMENT
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rcall LCD_WriteCommand
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ldi r16, HD44780_DISPLAY_ONOFF | HD44780_DISPLAY_ON | HD44780_CURSOR_OFF | HD44780_CURSOR_NOBLINK
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rcall LCD_WriteCommand
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ret
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;------------------------------------------------------------------------------
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; End of file
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;------------------------------------------------------------------------------
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