55 lines
824 B
NASM
55 lines
824 B
NASM
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; This example upon each reset increases the 8-bit counter stored in EEPROM
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; and then presents the bits of this value on the pins of port A.
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include "avr.inc"
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include "..\8051\hex.inc"
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include "m16def.inc"
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.org 0
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rjmp start
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start:
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ldi r16,RAMEND and $ff
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out spl,r16
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ldi r16,RAMEND shr 8
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out sph,r16
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ldi r16,$37
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call eeprom_read_byte
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mov r17,r16
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inc r17
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ldi r16,$37
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call eeprom_write_byte
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ldi r18,11111111b
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out DDRA,r18
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out PORTA,r17
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hang: jmp hang
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eeprom_read_byte:
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; r16 = EEPROM address
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; returns: r16 = byte data
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sbic EECR,EEWE
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jmp eeprom_read_byte
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out EEARL,r16
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sbi EECR,EERE
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in r16,EEDR
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ret
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eeprom_write_byte:
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; r16 = EEPROM address
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; r17 = byte data
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cli
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while_eeprom_busy:
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sbic EECR,EEWE
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jmp while_eeprom_busy
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out EEARL,r16
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out EEDR,r17
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sbi EECR,EEMWE
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sbi EECR,EEWE
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sei
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ret
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