uint8_t lcd_read(uint8_t rs) {
__IO uint8_t data;
if(rs) { //read data
lcd_rs_high();
} else { //read busy flag
lcd_rs_low();
}
lcd_rw_high(); // read mode
//set data pins to input
GPIO_InitStructure.GPIO_Pin = DATA_PORT_Pin_0 | DATA_PORT_Pin_1 |
DATA_PORT_Pin_2 | DATA_PORT_Pin_3;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;
GPIO_Init(LCD_PORT, &GPIO_InitStructure);
//read 2 nibbles
lcd_e_high(); //enable
lcd_e_delay();
data = (uint8_t)GPIO_ReadInputData(LCD_PORT) << 4;
lcd_e_low(); //disable
lcd_e_delay();
lcd_e_high(); //enable
lcd_e_delay();
data |= (uint8_t)GPIO_ReadInputData(LCD_PORT) & 0x0F;
lcd_e_low(); //disable
return data;
}
/**
* Writes a raw instruction to the LCD.
* @param command The 4-bit instruction code.
* @param data The 8-bit paramater/data to the specified instruction.
*/
void lcd_write_command(unsigned char command, unsigned char data) {
/* Wait for the busy flag to clear */
lcd_wait_busy();
/* Set Enable low, RW low, RS high to write the instruction command */
lcd_enable_low();
lcd_rw_low();
lcd_rs_high();
__asm("nop;"); __asm("nop;"); __asm("nop;");
__asm("nop;"); __asm("nop;"); __asm("nop;");
__asm("nop;"); __asm("nop;"); __asm("nop;");
/* Instruction commands are a maximum of 4 bits long, so
* just mask off the rest. */
LCD_DATA_PORT = (command&0x0F);
lcd_enable_high();
__asm("nop;"); __asm("nop;"); __asm("nop;");
__asm("nop;"); __asm("nop;"); __asm("nop;");
__asm("nop;"); __asm("nop;"); __asm("nop;");
/* Set RW low, RW low to write the instruction data */
lcd_rw_low();
lcd_rs_low();
LCD_DATA_PORT = data;
__asm("nop;"); __asm("nop;"); __asm("nop;");
__asm("nop;"); __asm("nop;"); __asm("nop;");
lcd_strobe_enable();
__asm("nop;"); __asm("nop;"); __asm("nop;");
__asm("nop;"); __asm("nop;"); __asm("nop;");
}
/**
* Initializes the LCD in graphics mode.
* Uses a character pitch of 8 (8 bits are plotted whenever a byte is drawn)
*/
void lcd_graphics_init(void) {
unsigned char commandData;
/* Set the data direction registers apprioriately */
LCD_DATA_DDR = 0xFF;
LCD_CTRL_DDR |= (1<<LCD_CTRL_RS)|(1<<LCD_CTRL_RW)|(1<<LCD_CTRL_E)|(1<<LCD_CTRL_CS)|(1<<LCD_CTRL_RST);
/* Assert all control lines to low */
lcd_rw_low();
lcd_enable_low();
/* Reset the LCD controllers */
lcd_rst_low();
_delay_ms(100); /* Delay for 100 ms */
lcd_rst_high();
_delay_ms(100); /* Delay for 100 ms */
/* Assert all registor control line to low */
lcd_rs_low();
/* Send mode configuration command with
* Toggle Display On, Master, Mode Graphics bits set */
commandData = LCD_MODE_ON_OFF | LCD_MODE_MASTER_SLAVE | LCD_MODE_MODE;
lcd_write_command(LCD_CMD_MODE, commandData);
/* Send the set character pitch command with horizontal
* character pitch of 8 (so 8 pixels are painted when we draw) */
commandData = LCD_CHAR_PITCH_HP_8;
lcd_write_command(LCD_CMD_CHAR_PITCH, commandData);
/* Send the number of characters command with the total
* number of graphics bytes that can be painted horizontally
* (width/8) */
commandData = (LCD_WIDTH/8)-1;
lcd_write_command(LCD_CMD_NUM_CHARS, commandData);
/* Set the time division */
commandData = 128-1;
lcd_write_command(LCD_CMD_TIME_DIVISION, commandData);
/* Set the display low/high start address to 0x00 (left corner) */
commandData = 0x00;
lcd_write_command(LCD_CMD_DISPLAY_START_LA, commandData);
lcd_write_command(LCD_CMD_DISPLAY_START_HA, commandData);
/* Reset the cursor to home 0x00 (left corner) */
commandData = 0x00;
lcd_write_command(LCD_CMD_CURSOR_LA, commandData);
lcd_write_command(LCD_CMD_CURSOR_HA, commandData);
}
//-----------------------------------------------------------------------------------------
// FUNCTION: lcd_write
// PURPOSE: send a character or an instruction to the LCD
void lcd_write(uint8_t data, uint8_t rs)
{
_delay_us(1000);
//check write type
if (rs)
lcd_rs_high(); //write data
else
lcd_rs_low(); //write instruciton
// configure data pins as output
LCD_DDR(LCD_DATA0_PORT) |= _BV(LCD_DATA0_PIN);
LCD_DDR(LCD_DATA1_PORT) |= _BV(LCD_DATA1_PIN);
LCD_DDR(LCD_DATA2_PORT) |= _BV(LCD_DATA2_PIN);
LCD_DDR(LCD_DATA3_PORT) |= _BV(LCD_DATA3_PIN);
// output high nibble first
LCD_DATA3_PORT &= ~_BV(LCD_DATA3_PIN);
LCD_DATA2_PORT &= ~_BV(LCD_DATA2_PIN);
LCD_DATA1_PORT &= ~_BV(LCD_DATA1_PIN);
LCD_DATA0_PORT &= ~_BV(LCD_DATA0_PIN);
if(data & 0x80) LCD_DATA3_PORT |= _BV(LCD_DATA3_PIN);
if(data & 0x40) LCD_DATA2_PORT |= _BV(LCD_DATA2_PIN);
if(data & 0x20) LCD_DATA1_PORT |= _BV(LCD_DATA1_PIN);
if(data & 0x10) LCD_DATA0_PORT |= _BV(LCD_DATA0_PIN);
lcd_toggle_e();
// output low nibble
LCD_DATA3_PORT &= ~_BV(LCD_DATA3_PIN);
LCD_DATA2_PORT &= ~_BV(LCD_DATA2_PIN);
LCD_DATA1_PORT &= ~_BV(LCD_DATA1_PIN);
LCD_DATA0_PORT &= ~_BV(LCD_DATA0_PIN);
if(data & 0x08) LCD_DATA3_PORT |= _BV(LCD_DATA3_PIN);
if(data & 0x04) LCD_DATA2_PORT |= _BV(LCD_DATA2_PIN);
if(data & 0x02) LCD_DATA1_PORT |= _BV(LCD_DATA1_PIN);
if(data & 0x01) LCD_DATA0_PORT |= _BV(LCD_DATA0_PIN);
lcd_toggle_e();
// all data pins high (inactive)
LCD_DATA0_PORT |= _BV(LCD_DATA0_PIN);
LCD_DATA1_PORT |= _BV(LCD_DATA1_PIN);
LCD_DATA2_PORT |= _BV(LCD_DATA2_PIN);
LCD_DATA3_PORT |= _BV(LCD_DATA3_PIN);
}
// PURPOSE: send a character or an instruction to the LCD
void HD44780::lcd_write(uint8_t data,uint8_t rs)
{
// we cannot check LCD status (no read available) , so we will assume a default delay to wait for lcd to be ready
fcpu_delay_us(500);
//check write type
if (rs)
lcd_rs_high(); //write data
else
lcd_rs_low(); //write instruciton
// configure data pins as output
LCD_DDR(LCD_4BIT_D4_PORT) |= _BV(LCD_4BIT_D4_PIN);
LCD_DDR(LCD_4BIT_D5_PORT) |= _BV(LCD_4BIT_D5_PIN);
LCD_DDR(LCD_4BIT_D6_PORT) |= _BV(LCD_4BIT_D6_PIN);
LCD_DDR(LCD_4BIT_D7_PORT) |= _BV(LCD_4BIT_D7_PIN);
// output high nibble first
LCD_4BIT_D7_PORT &= ~_BV(LCD_4BIT_D7_PIN);
LCD_4BIT_D6_PORT &= ~_BV(LCD_4BIT_D6_PIN);
LCD_4BIT_D5_PORT &= ~_BV(LCD_4BIT_D5_PIN);
LCD_4BIT_D4_PORT &= ~_BV(LCD_4BIT_D4_PIN);
if(data & 0x80) LCD_4BIT_D7_PORT |= _BV(LCD_4BIT_D7_PIN);
if(data & 0x40) LCD_4BIT_D6_PORT |= _BV(LCD_4BIT_D6_PIN);
if(data & 0x20) LCD_4BIT_D5_PORT |= _BV(LCD_4BIT_D5_PIN);
if(data & 0x10) LCD_4BIT_D4_PORT |= _BV(LCD_4BIT_D4_PIN);
lcd_toggle_e();
// output low nibble
LCD_4BIT_D7_PORT &= ~_BV(LCD_4BIT_D7_PIN);
LCD_4BIT_D6_PORT &= ~_BV(LCD_4BIT_D6_PIN);
LCD_4BIT_D5_PORT &= ~_BV(LCD_4BIT_D5_PIN);
LCD_4BIT_D4_PORT &= ~_BV(LCD_4BIT_D4_PIN);
if(data & 0x08) LCD_4BIT_D7_PORT |= _BV(LCD_4BIT_D7_PIN);
if(data & 0x04) LCD_4BIT_D6_PORT |= _BV(LCD_4BIT_D6_PIN);
if(data & 0x02) LCD_4BIT_D5_PORT |= _BV(LCD_4BIT_D5_PIN);
if(data & 0x01) LCD_4BIT_D4_PORT |= _BV(LCD_4BIT_D4_PIN);
lcd_toggle_e();
// all data pins high (inactive)
LCD_4BIT_D4_PORT |= _BV(LCD_4BIT_D4_PIN);
LCD_4BIT_D5_PORT |= _BV(LCD_4BIT_D5_PIN);
LCD_4BIT_D6_PORT |= _BV(LCD_4BIT_D6_PIN);
LCD_4BIT_D7_PORT |= _BV(LCD_4BIT_D7_PIN);
}
void lcd_write(uint8_t data, uint8_t rs) {
__IO uint8_t outputdata;
if(rs) { //write data
lcd_rs_high();
} else { //write instruction
lcd_rs_low();
}
lcd_rw_low(); //set to write
//set data pins to output
GPIO_InitStructure.GPIO_Pin = DATA_PORT_Pin_0 | DATA_PORT_Pin_1 |
DATA_PORT_Pin_2 | DATA_PORT_Pin_3;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_Init(LCD_PORT, &GPIO_InitStructure);
/**
* Preserve the RS,RW,E bits in order to write out:
* our data goe son the 4 most significant bits with
* the high nibble output first.
*/
outputdata = (uint8_t)GPIO_ReadOutputData(LCD_PORT);
outputdata &= 0x05; //we're only interested in the lower bits (RS,RW,E)
//output high nibble first
GPIO_Write(LCD_PORT, outputdata | (data & 0xF0));
//push data
lcd_e_toggle();
GPIO_Write(LCD_PORT, outputdata | ((data << 4) & 0xF0));
//push data
lcd_e_toggle();
GPIO_Write(LCD_PORT, outputdata | 0xF0); //set pins high as inactive state
}
