First, The LCD is working in 8Bit mode but that was just for testing. Now I need to work in 4Bit mode and I can't get it to work, I've tried for hours :(

The model is PC1602F and I'm not sure if its capible of 4bit or even if its HD44780 compatible.

So I followed this diagram from HD44780 datasheet:



And the code I've used:



#define LCD_RS P3_6
#define LCD_E P3_7
#define LCD_BUS_PORT P0

void main() {
//Power on
//Wait more than 15 msecs after power is applied.
delay_ms(40);

LCD_RS = 0; //instructions

LCD_BUS_PORT |= 0x30;
E_clk();
delay_ms(10);

LCD_BUS_PORT |= 0x30;
E_clk();

LCD_BUS_PORT |= 0x30;
E_clk();

LCD_BUS_PORT |= 0x20;
E_clk();

//0x28 (4Bit mode,2Lines,Small font)
LCD_BUS_PORT |= 0x20;
E_clk();
LCD_BUS_PORT |= 0x80;
E_clk();

//0x08 (Display off)
LCD_BUS_PORT |= 0x00;
E_clk();
LCD_BUS_PORT |= 0x80;
E_clk();

//0x01 (Clear the display)
LCD_BUS_PORT |= 0x00;
E_clk();
LCD_BUS_PORT |= 0x10;
E_clk();

//0x06 (Entry mode - no shifting, auto increase)
LCD_BUS_PORT |= 0x00;
E_clk();
LCD_BUS_PORT |= 0x60;
E_clk();

while(1);
}


void E_clk() {
delay_ms(1);
LCD_E =0;
delay_ms(1);
LCD_E=1;
delay_ms(1);
LCD_E =0;
}


I don't know get the tabs or spaces to work with the
code I pasted, you can still view it in full here (with tabs): View

• delay_ms is a function that uses timer1 to delay the required amount in miliseconds (Tested to work)


• P0 has external pullups even if they are not required


• I have disconnected d0-d3 on the LCD after I tested it with 8bit operation.

Only first line of the two is lit only with every character black.

Any ideas?

Thanks,
Paul.