rgbyteclock-code/lcd.c

/*
 * "THE BEER-WARE LICENSE" (Revision 42):
 * Martin Wenger <martin.wenger@arcormail.de> and Stefan Rupp <struppi@struppi.name>
 * wrote this file. As long as you retain this notice you can do whatever you want
 * with this stuff. If we meet some day, and you think this stuff is worth it,
 * you can buy me/us a beer in return.
 * (c) 2005-2010 Martin Wenger, Stefan Rupp
 * (c) 2014 Stefan Rupp
 */

#include <avr/io.h>
#include <inttypes.h>
#include <string.h>
#include <compat/ina90.h>    // ==> _NOP()

#include "timer.h"
#include "lcd.h"

#define LCD_DATA_PIN   (PINA)
#define LCD_DATA_PORT  (PORTA)
#define LCD_DATA_DIR   (DDRA)
#define LCD_DATA_MASK  (0x0f)



#if (F_CPU <= 4000000UL)
#define WAIT_250_ns()       _NOP()
#elif (F_CPU <= 8000000UL)
#define WAIT_250_ns()       _NOP();_NOP()
#elif (F_CPU <= 12000000UL)
#define WAIT_250_ns()       _NOP();_NOP();_NOP()
#elif (F_CPU <= 16000000UL)
#define WAIT_250_ns()       _NOP();_NOP();_NOP();_NOP()
#elif (F_CPU <= 20000000UL)
#define WAIT_250_ns()       _NOP();_NOP();_NOP();_NOP();_NOP()
#else
#include <util/delay.h>
#define WAIT_250_ns()       _delay_us(1)
#endif

#define LCD_DATA_MODE()     (PORTA |=  (1<<PA4))
#define LCD_CMD_MODE()      (PORTA &= ~(1<<PA4))

#define LCD_SET_ENABLE()    (PORTA |=  (1<<PA6))
#define LCD_RESET_ENABLE()  (PORTA &= ~(1<<PA6))

// !!!!!!!
#define LCD_SET_READ()      LCD_DATA_DIR &= ~(LCD_DATA_MASK);LCD_DATA_PORT &= ~(LCD_DATA_MASK);PORTA |= (1<<PA5)
#define LCD_SET_WRITE()     PORTA &= ~(1<<PA5);LCD_DATA_DIR |= LCD_DATA_MASK
// !!!!!!!


#define T_TIMEOUT (10)

static uint8_t lcd_initialized;


static inline uint8_t lcd_read_byte(uint8_t RS)
{
  uint8_t byte;

  if (RS)
    LCD_DATA_MODE();
  else
    LCD_CMD_MODE();

  LCD_SET_READ();
  
  LCD_SET_ENABLE();
  WAIT_250_ns();
  byte = (LCD_DATA_PIN<<4);
  LCD_RESET_ENABLE();
  
  WAIT_250_ns();
  WAIT_250_ns();
  
  LCD_SET_ENABLE();
  WAIT_250_ns();
  byte |= LCD_DATA_PIN & 0x0f;
  LCD_RESET_ENABLE();
  
  return byte;  
}


static inline int8_t lcd_wait_while_busy(void)
{
  
  uint8_t byte;
  uint32_t t_enter = timer_get();

  do {
	if (timer_get() > t_enter + T_TIMEOUT) {
		return 0;
	}
    byte = lcd_read_byte(0);
  } while (byte & 0x80);
  return 1;
}


static inline void send_nibble(uint8_t nibble)
{
  LCD_SET_WRITE();
  LCD_DATA_PORT = (LCD_DATA_PORT & 0xf0) | (0x0f & nibble);
  LCD_SET_ENABLE();
  WAIT_250_ns();
  LCD_RESET_ENABLE();
}


/**
  * Send one byte to the LCD
  * \param byte The byte to send to the LCD
  * \param RS specifies whether byte sent is data (RS==1) or command (RS==0)
  */
static inline int8_t lcd_send_byte(uint8_t byte, uint8_t RS)
{
  if (lcd_wait_while_busy() ) {
	  if (RS)
		  LCD_DATA_MODE();
	  else
		  LCD_CMD_MODE();

	  send_nibble(byte >> 4);
	  _NOP();
	  send_nibble(0x0f & byte);
	  return 1;
  }
  return 0;
}


int lcd_get(void)
{
	if ( lcd_wait_while_busy() ) {
		return lcd_read_byte(1);
	}
	return -1;
}

int lcd_put(char c)
{
	if (!lcd_initialized) {
		return 0;
	}
	return lcd_send_byte(c, 1);
}

void lcd_puts(char *s)
{
	if (!lcd_initialized) {
		return;
	}
	
  while (*s) {
    //lcd_put(*s++);
	  if (!lcd_send_byte(*s++, 1)) {
		  return;
	  }
  }
  return;
}

void lcd_cursor(uint8_t blink)
{
  if (blink) {
    // enable display with cursor + blinking
	lcd_send_byte(0x0f, 0);
  }
  else  {
    // enable display, no cursor, no blinking
    lcd_send_byte(0x0c, 0);
  return;
  }
}

void lcd_init(void)
{
  /* Initialize both ATmega and Display
   * After return from this function,
   * display we be set to 4-bit data mode
   */
  
	lcd_initialized = 0;

  // wait until LCD gets ready to accept instructions.
  timer_wait(50);

  // set CONTROL Pins as outputs:
  DDRA |= (0x70);

  LCD_CMD_MODE();
  LCD_SET_WRITE();

  // set LCD to 8-bit mode
  send_nibble(0x03);
  
  timer_wait(5);
  send_nibble(0x03);
  
  timer_wait(5);
  send_nibble(0x03);
  
  // LCD definitely is in 8-bit mode now
  
  // set module to 4-bit mode now
  // Remember! As we're in 8-bit mode now,
  // send_nibble is the right thing, not send_byte!
  timer_wait(5);
  send_nibble(0x02);
  timer_wait(5);

  // set to 5 x 8 dots per character,
  // 16 characters per line, 2 lines
  int success = lcd_send_byte(0x28, 0);

  if ( !success ) {
	  return;
  }

  // enable display, no cursor, no blinking
  //lcd_send_byte(0x0c, 0);
  // enable display with cursor + blinking
  //lcd_send_byte(0x0f, 0);
  lcd_cursor(1);
  
  // Set display to
  // + Move cursor (and do not shift display)
  // + Move right
  lcd_send_byte(0x04, 0);
  
  // clear dislay
  lcd_clear();

  lcd_initialized = 1;
 
  return;
}

void lcd_clear(void)
{
  lcd_send_byte(0x01, 0);
}

void lcd_locate(uint8_t row, uint8_t col)
{
	if (!lcd_initialized) {
		return;
	}

  if (row)
    col += 0x40;
  lcd_send_byte(0x80 + col, 0);
}