hello
I try to use a display: DOG-m 183 (4bits, 1line, 8char) with a 18f452.
and the library by Richard Zengerink:"lcd_dog_m4"
My problem is : when transferring datas to the display, only first high
nibble is correctly transmitted, the second nibble is always 1111.
here is my procedures:
var byte lcd_dataport is PORTA_low --only the low port connected a0, a1,
a2 a3
var bit lcd_en is pin_a5
--E d4, d5 ,d6, d7
var bit lcd_rs is pin_a4 --RS
PORTA_direction=all_output
pin_a4_direction=output
pin_a5_direction=output
procedure lcd_w(byte in value) is
--pragma inline
lcd_dataport = (value>>4)
lcd_en=high --lcd E for data
asm nop --400ns with 10MHz xtal
lcd_en=low
lcd_dataport= value
lcd_en=high
asm nop
lcd_en=low
end procedure
-- and the init sequence
procedure lcd_init is
delay_1ms(50)
LCD_wi(0b_0010_0000) --function :4bit 1 line , is1
LCD_wi(0b_0010_0001) --function :is1
LCD_wi(0b_0001_0100) --bias : 1/4
LCD_wi(0b_0111_0000) --contrast
LCD_wi(0b_0101_1110) --pwr control
LCD_wi(0b_0110_1010) --follower
LCD_wi(0b_0011_1000) --function
LCD_wi(0b_0000_1000) --display :display on/ cursor off
LCD_wi(0b_0000_0001) --clr display , cursor at home
LCD_wi(0b_0000_0110) --entry mode set : cursor moves ->
delay_10us(4)
end procedure:
When I try to send a char data to the display, the first HIGH nibble is
read, the second LOW is read as 1111
I don't understand where is the bug.
If someone experienced the same probleme........
Thanks in advance
Phil
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