8051 OLED Procs

void OLED_wrnibble(unsigned char hbyte, bit reg)
{
    rs_lcd = reg; lcd_rd = 0;
    delay_timer_us(50);


    P0&=0xf0;
    P0|=hbyte;
    e_lcd = 1;



    delay_timer_us(50);
    e_lcd = 0;

    return;

}

void OLED_busy_wait(void)
{
    unsigned char temp;
    bit bFlag = 0;

    do{
        rs_lcd = 0; lcd_rd = 1;
        e_lcd = 0;
        P0|=0x0f;

        e_lcd = 1;
        delay_timer_us(11);
        temp = (P0&0x0f)<<4;
        e_lcd = 0;


        e_lcd = 1;
        delay_timer_us(50);
        temp|= (P0&0x0f);
        e_lcd = 0;
    }while (temp&0x80);

    return;
}

void OLED_wrbyte(unsigned char byte, bit reg)
{
    volatile unsigned char temp;

    rs_lcd = reg; lcd_rd = 0;
    temp = (byte >> 4)&0x0f;

    delay_timer_us(50);


    P0&=0xf0;
    P0|=temp;
    e_lcd = 1;
    delay_timer_us(50);
    e_lcd = 0;

    temp = byte&0x0f;

    delay_timer_us(50);


    P0&=0xf0;
    P0|=temp;
    e_lcd = 1;
    delay_timer_us(50);
    e_lcd = 0;

    OLED_busy_wait();

    return;

}