m820241125007LCD.asm

; 2024-11-25
; LCD
; (C) David Vajda

.include "m8def.inc"

ldi r16, HIGH (RAMEND)
out SPH, r16
ldi r16, LOW (RAMEND)
out SPL, r16

ldi r16, 0xff
out DDRD, r16

rcall lcd_init
ldi r16, 0b00000001
rcall lcd_cmd
ldi r16, 0b00000010
rcall lcd_cmd
ldi r16, 'h'
rcall lcd_data
ldi r16, 't'
rcall lcd_data
ldi r16, 't'
rcall lcd_data
ldi r16, 'p'
rcall lcd_data
ldi r16, 's'
rcall lcd_data
ldi r16, ':'
rcall lcd_data
ldi r16, '/'
rcall lcd_data
ldi r16, '/'
rcall lcd_data
ldi r16, 'w'
rcall lcd_data
ldi r16, 'w'
rcall lcd_data
ldi r16, 'w'
rcall lcd_data
ldi r16, '.'
rcall lcd_data
ldi r16, 'i'
rcall lcd_data
ldi r16, 't'
rcall lcd_data
ldi r16, 'u'
rcall lcd_data
ldi r16, 'e'
rcall lcd_data
ldi r16, 'n'
rcall lcd_data
ldi r16, 'i'
rcall lcd_data
ldi r16, 'x'
rcall lcd_data
ldi r16, '.'
rcall lcd_data
ldi r16, 'd'
rcall lcd_data
ldi r16, 'e'
rcall lcd_data

end: rjmp end

sleep:
push r16
ldi r16, 0xff
sleep_loop1:
dec r16
brne sleep_loop1
pop r16
ret

enable:
sbi PORTD, 5
nop
nop
nop
cbi PORTD, 5
ret

lcd_init:
rcall sleep
ldi r16, 0x03
rcall lcd_cmd8
ldi r16, 0x03
rcall lcd_cmd8
ldi r16, 0x03
rcall lcd_cmd8
ldi r16, 0x02
rcall lcd_cmd
ldi r16, 0x20
rcall lcd_cmd
ret

lcd_cmd8:
out PORTD, r16
rcall enable
rcall sleep
ret


lcd_cmd:
mov r17, r16
swap r16
andi r16, 0x0f
andi r17, 0x0f
out PORTD, r16
rcall enable
out PORTD, r17
rcall enable
rcall sleep
ret

lcd_data:
mov r17, r16
swap r16
andi r16, 0x0f
andi r17, 0x0f
ori r16, 0b00010000
ori r17, 0b00010000
out PORTD, r16
rcall enable
out PORTD, r17
rcall enable
rcall sleep
ret