fw/lcd.c (21e3f0f) - mips_sys · BlinkenArea

lcd.c

#include "cyc_cnt.h"
#include "lcd.h"

static volatile unsigned char *const lcd_ptr =
  (volatile unsigned char *)0x80000100;

/**
 * @brief set data to LCD
 * @param[in] data data to LCD
 */
void lcd_set_data(unsigned char data)
{
  lcd_ptr[0] = data;
}

/**
 * @brief set enable signal to LCD
 * @param[in] state state for enable signal (0 or 1)
 */
void lcd_set_e(unsigned char state)
{
  lcd_ptr[1] = state;
}

/**
 * @brief set register select signal to LCD
 * @param[in] state state for register select signal (0 or 1)
 */
void lcd_set_rs(unsigned char state)
{
  lcd_ptr[2] = state;
}

/**
 * @brief set read/write signal to LCD
 * @param[in] state state for read/write signal (0 or 1)
 */
void lcd_set_rw(unsigned char state)
{
  volatile unsigned char *p_lcd_rw = (volatile unsigned char *)0x80000103;
  lcd_ptr[3] = state;
}

/** set LCD to 4 bit mode */
void lcd_set4bit(void)
{
  lcd_set_data(0x0F);
  lcd_set_e(0);
  lcd_set_rs(0);
  lcd_set_rw(0);
  cyc_cnt_delay_ms(15);
  lcd_set_data(0x3F);
  lcd_set_e(1);
  cyc_cnt_delay(12);
  lcd_set_e(0);
  cyc_cnt_delay_us(4100);
  lcd_set_e(1);
  cyc_cnt_delay(12);
  lcd_set_e(0);
  cyc_cnt_delay_us(100);
  lcd_set_e(1);
  cyc_cnt_delay(12);
  lcd_set_e(0);
  cyc_cnt_delay_us(40);
  lcd_set_data(0x2F);
  lcd_set_e(1);
  cyc_cnt_delay(12);
  lcd_set_e(0);
  cyc_cnt_delay_us(40);
}

/**
 * @brief output a byte to LCD
 * @param[in] data if the byte is a data byte (command otherwise)
 * @param[in] byte byte to write
 */
void lcd_byte(unsigned char data, unsigned char byte)
{
  lcd_set_e(0);
  lcd_set_rs(data ? 1: 0);
  lcd_set_rw(0);
  lcd_set_data(byte | 0x0F);
  lcd_set_e(1);
  cyc_cnt_delay(12);
  lcd_set_e(0);
  cyc_cnt_delay_us(1);
  lcd_set_data(byte << 4 | 0x0F);
  lcd_set_e(1);
  cyc_cnt_delay(12);
  lcd_set_e(0);
  cyc_cnt_delay_us(40);
}

/** initialize LCD */
void lcd_init(void)
{
  lcd_set4bit();
  lcd_byte(0, 0x28);
  lcd_byte(0, 0x06);
  lcd_byte(0, 0x0C);
  lcd_byte(0, 0x01);
  cyc_cnt_delay_us(1640);
  lcd_byte(1, 'H');
  lcd_byte(1, 'e');
  lcd_byte(1, 'l');
  lcd_byte(1, 'l');
  lcd_byte(1, 'o');
  lcd_byte(1, ' ');
  lcd_byte(1, 'W');
  lcd_byte(1, 'o');
  lcd_byte(1, 'r');
  lcd_byte(1, 'l');
  lcd_byte(1, 'd');
  lcd_byte(1, '!');
}

mips_sys

converted code to use constants in data memory