First steps towards character LCD

1 files changed, 527 insertions, 0 deletions

diff --git a/3rd-party/LCDHD44780.c b/3rd-party/LCDHD44780.c
new file mode 100644
index 0000000..32c8ce2
--- /dev/null
+++ b/3rd-party/LCDHD44780.c
@@ -0,0 +1,527 @@
+/*##############################################################*/
+/* Author: Marcus Nasarek                                       */
+/* File:   LCDH44780.c                                          */
+/* Compile with:                                                */
+/*      gcc -Wall -c LCDHD44780.c -o LCDHD44780.o               */
+/* License:                                                     */
+/*                                                              */
+/*  This program is free software; you can redistribute it      */
+/*  and/or modify it under the terms of the GNU General         */
+/*  Public License as published by the Free Software            */
+/*  Foundation; either version 3 of the License, or             */
+/*  (at your option) any later version.                         */
+/*                                                              */
+/*  This program is distributed in the hope that it will        */
+/*  be useful, but WITHOUT ANY WARRANTY; without even the       */
+/*  implied warranty of MERCHANTABILITY or                      */
+/*  FITNESS FOR A PARTICULAR PURPOSE. See the GNU General       */
+/*  Public License for more details.                            */
+/*                                                              */
+/*  You should have received a copy of the GNU General          */
+/*  Public License along with this program; if not,             */
+/*  see <http://www.gnu.org/licenses/>.                         */
+/*                                                              */
+/*##############################################################*/
+
+#include "LCDHD44780.h"
+
+void init_gpio(void)
+{
+	// Set all pins to output
+	bcm2835_gpio_fsel(LCD_RS, BCM2835_GPIO_FSEL_OUTP);
+	bcm2835_gpio_fsel(LCD_RW, BCM2835_GPIO_FSEL_OUTP);
+	bcm2835_gpio_fsel(LCD_D4, BCM2835_GPIO_FSEL_OUTP);
+	bcm2835_gpio_fsel(LCD_D5, BCM2835_GPIO_FSEL_OUTP);
+	bcm2835_gpio_fsel(LCD_D6, BCM2835_GPIO_FSEL_OUTP);
+	bcm2835_gpio_fsel(LCD_D7, BCM2835_GPIO_FSEL_OUTP);
+	bcm2835_gpio_fsel(LCD_E,  BCM2835_GPIO_FSEL_OUTP);
+
+	bcm2835_delayMicroseconds(C_DELAY);
+
+	// Set all pins to LOW
+	bcm2835_gpio_clr(LCD_RS);
+	bcm2835_gpio_clr(LCD_RW);
+	bcm2835_gpio_clr(LCD_D4);
+	bcm2835_gpio_clr(LCD_D5);
+	bcm2835_gpio_clr(LCD_D5);
+	bcm2835_gpio_clr(LCD_D7);
+	bcm2835_gpio_clr(LCD_E);
+
+}
+
+void set_data_pins_to_output(void)
+{
+		// set data pins to output
+	bcm2835_gpio_fsel(LCD_D7, BCM2835_GPIO_FSEL_OUTP);
+	bcm2835_gpio_fsel(LCD_D6, BCM2835_GPIO_FSEL_OUTP);
+	bcm2835_gpio_fsel(LCD_D5, BCM2835_GPIO_FSEL_OUTP);
+	bcm2835_gpio_fsel(LCD_D4, BCM2835_GPIO_FSEL_OUTP);
+}
+
+void set_data_pins_to_input(void)
+{
+	// set data pins to input
+	bcm2835_gpio_fsel(LCD_D7, BCM2835_GPIO_FSEL_INPT);
+	bcm2835_gpio_fsel(LCD_D6, BCM2835_GPIO_FSEL_INPT);
+	bcm2835_gpio_fsel(LCD_D5, BCM2835_GPIO_FSEL_INPT);
+	bcm2835_gpio_fsel(LCD_D4, BCM2835_GPIO_FSEL_INPT);
+}
+
+void pulse_e(void)
+{
+	// Toogle ENABLE pin in us
+	// bcm2835_gpio_fsel(LCD_E, BCM2835_GPIO_FSEL_OUTP);
+	bcm2835_delayMicroseconds(E_DELAY);
+	bcm2835_gpio_set(LCD_E);
+	bcm2835_delayMicroseconds(E_DATA_PULSE);
+	bcm2835_gpio_clr(LCD_E);
+	(LCD_DATA) ? bcm2835_delayMicroseconds(E_DATA_PULSE) :bcm2835_delayMicroseconds(E_CMD_PULSE);
+}
+
+uint8_t busy_wait(void)
+{
+	// FIXME: this function does not work!
+	// With RW grounded it shouldn't work.
+	// But as long as the display is driven
+	// by 5V the GPIO ports on a raspberry pi
+	// would get to much voltage
+
+	uint8_t addr;
+	bool wait = true;
+	uint16_t counter = 0;
+
+	set_data_pins_to_input();
+
+	bcm2835_gpio_clr(LCD_RS);
+	bcm2835_gpio_set(LCD_RW);
+
+	while(wait && (counter < MAX_WAIT))
+	{
+		addr = 0;
+		pulse_e();
+
+		// read high bits
+		if (bcm2835_gpio_lev(LCD_D4))
+			addr = (addr | 0x10);
+		if (bcm2835_gpio_lev(LCD_D5))
+			addr = (addr | 0x20);
+		if (bcm2835_gpio_lev(LCD_D6))
+			addr = (addr | 0x40);
+		if (bcm2835_gpio_lev(LCD_D7))
+			addr = (addr | 0x80);
+
+		// Toogle ENABLE pin in us
+		pulse_e();
+
+		// read low bits
+		if (bcm2835_gpio_lev(LCD_D4))
+			addr = (addr | 0x01);
+		if (bcm2835_gpio_lev(LCD_D5))
+			addr = (addr | 0x02);
+		if (bcm2835_gpio_lev(LCD_D6))
+			addr = (addr | 0x04);
+		if (bcm2835_gpio_lev(LCD_D7))
+			addr = (addr | 0x08);
+
+		wait = (addr & 0x80);
+		counter += 1;
+
+		bcm2835_delay(1);
+	}
+
+	bcm2835_gpio_clr(LCD_RW);
+	set_data_pins_to_output();
+
+	// return address but mask out highest bit (busy flag)
+	// 0x7F = 0 1 1 1  1 1 1 1
+	return (addr & 0x7F);
+}
+
+void init_lcd(void)
+{
+	init_gpio();
+
+	/*
+	The busy flag (BF) is kept in the busy state
+	until the initialization ends (BF = 1). The
+	busy state lasts for 10 ms after VCC rises to 4.5 V
+	*/
+
+	/*
+	--- symbols:
+	I/D = 1: Increment
+	I/D = 0: Decrement
+	S = 1: Accompanies display shift
+	S/C = 1: Display shift
+	S/C = 0: Cursor move
+	R/L = 1: Shift to the right
+	R/L = 0: Shift to the left
+	DL = 1: 8 bits, DL = 0: 4 bits
+	N = 1: 2 lines, N = 0: 1 line
+	F = 1: 5
+	×
+	10 dots, F = 0: 5
+	×
+	8 dots
+	BF = 1: Internally operating
+	BF = 0: Instructions acceptable
+	*/
+
+	/*
+	--- Display init after turn on:
+	1. Display clear
+	2. Function set:
+			DL = 1; 8-bit interface data
+			N = 0; 1-line display
+			F = 0; 5×8 dot character font
+	3. Display on/off control:
+			D = 0; Display off
+			C = 0; Cursor off
+			B = 0; Blinking off
+	4. Entry mode set:
+			I/D = 1; Increment by 1
+			S = 0; No shift
+	*/
+
+	// begin of "warming up"
+	// see fig 24 on page 46 of datasheet
+
+	// Function set -
+	// Sets interface data length
+	// (DL), number of display lines
+	// (N), and character font (F).
+	// RS R/W DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
+	// 0  0   0   0   1   DL   N   F   -   -
+	// DL = 0 --> 4 bit data length (1 = 8 bit)
+	// N = 1 --> 2 line display (0 = 1 line)
+	// F = 0 --> 5x8 dot character font
+	// 0x33 =
+	// 0  0   0   0   1   1    0   0   1   1
+	// --> ?
+	write_to_lcd(0x33, LCD_CMD);
+	bcm2835_delayMicroseconds(100);
+
+	// Function set -
+	// Sets interface data length
+	// (DL), number of display lines
+	// (N), and character font (F).
+	// RS R/W DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
+	// 0  0   0   0   1   DL   N   F   -   -
+	// DL = 0 --> 4 bit data length (1 = 8 bit)
+	// N = 1 --> 2 line display (0 = 1 line)
+	// F = 0 --> 5x8 dot character font
+	// 0x32 =
+	// 0  0   0   0   1   1    0   0   1   0
+	// --> ?
+	write_to_lcd(0x32, LCD_CMD);
+	bcm2835_delayMicroseconds(R_EXEC_TIME);
+
+	// end of "warming up"
+
+	lcd_function_set(TWO_LINES);
+
+	lcd_control(DISPLAY_ON);
+
+	lcd_entry_mode(ADDR_INCREMENT);
+
+	clear_lcd();
+
+}
+
+void lcd_function_set(uint8_t control_flags)
+{
+	// Function set -
+	// Sets interface data length
+	// (DL), number of display lines
+	// (N), and character font (F).
+	// RS R/W DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
+	// 0  0   0   0   1   DL   N   F   -   -
+	// DL = 0 --> 4 bit data length (1 = 8 bit)
+	// N = 1 --> 2 line display (0 = 1 line)
+	// F = 0 --> 5x8 dot character font
+	// F = 1 --> 5x10 dot character font
+	// 0x28 =
+	// 0  0   0   0   1   0    1  0   0   0
+	write_to_lcd(LCD_FUNCTION_SET | control_flags, LCD_CMD);
+	bcm2835_delayMicroseconds(R_EXEC_TIME);
+}
+
+void lcd_control(uint8_t control_flags)
+{
+	// Display on/off control -
+	// Sets entire display (D) on/off,
+	// cursor on/off (C), and
+	// blinking of cursor position
+	// character (B).
+	// RS R/W DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
+	// 0  0   0   0   0   0   1   D   C   B
+	// D = 1 --> display on
+	// C = 0 --> cursor off
+	// B = 0 --> blinking off
+	write_to_lcd(LCD_CONTROL | control_flags, LCD_CMD);
+	bcm2835_delayMicroseconds(R_EXEC_TIME);
+}
+
+void lcd_shift_control(uint8_t control_flags)
+{
+	// Cursor or display shift -
+	// Moves the cursor and shifts
+	// display without chaning
+	// DDRAM contents.
+	// Execution time 37us
+	// RS R/W DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
+	// 0  0   0   0   0   1   S/C R/L -   -
+	// S/C = cursor/display shift
+	// S/C = 0 --> cursor shift
+	// R/L = shift direction
+	// R/L = 1 --> shift to right
+	write_to_lcd(CURSOR_DISPLAY_SHIFT | control_flags, LCD_CMD);
+	bcm2835_delayMicroseconds(R_EXEC_TIME);
+}
+
+void lcd_entry_mode(uint8_t control_flags)
+{
+	// Entry mode set -
+	// Sets cursor move direction
+	// and specifies display shift.
+	// These operations are
+	// performed during data write
+	// and read.
+	// Execution time 37us
+	// RS R/W DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
+	// 0  0   0   0   0   0   0   1   I/D S
+	// I/D = increment/decrement address pointer
+	// I/D = 1 --> increment
+	// S = 0 --> no shift
+	write_to_lcd(LCD_ENTRY_MODE | control_flags, LCD_CMD);
+	bcm2835_delayMicroseconds(R_EXEC_TIME);
+}
+
+void clear_lcd(void) {
+	// Clear display -
+	// Clears entire display and
+	// sets DDRAM address 0 in
+	// address counter:
+	// RS R/W DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
+	// 0  0   0   0   0   0   0   0   0   1
+	write_to_lcd(0x01, LCD_CMD);
+	bcm2835_delayMicroseconds(R_EXEC_TIME);
+}
+
+void return_home(void)
+{
+	// Return home -
+	// Sets DDRAM address to 0
+	// in address counter. Also
+	// returns display from being
+	// shifted to original position
+	// DDRAM contents remains unchanged
+	// RS R/W DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
+	// 0  0   0   0   0   0   0   0   1   -
+	write_to_lcd(0x02, LCD_CMD);
+	bcm2835_delayMicroseconds(R_EXEC_TIME);
+}
+
+
+void display_off(void)
+{
+	lcd_control(DISPLAY_OFF);
+}
+
+void show_cursor(bool on)
+{
+	uint8_t cursor_flag;
+	cursor_flag = ( on ? CURSOR_ON : 0x00);
+	lcd_control(DISPLAY_ON | cursor_flag);
+}
+
+void cursor_blinking(bool on)
+{
+	uint8_t blinking_flag;
+	blinking_flag = ( on ? BLINKING_ON : 0x00);
+	lcd_control(DISPLAY_ON | blinking_flag);
+}
+
+void set_cursor(uint8_t addr)
+{
+	// Set DDRAM address
+	// RS R/W DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
+	// 0  0   1   ADD ADD ADD ADD ADD ADD ADD
+	write_to_lcd(addr, LCD_CMD);
+	bcm2835_delayMicroseconds(R_EXEC_TIME);
+	// fprintf(stdout,"cursor on addr: 0x%0x\n", addr);
+}
+
+void shift_cursor(uint8_t direction)
+{
+	lcd_shift_control(CURSOR_SHIFT | direction);
+}
+
+void shift_display(uint8_t direction)
+{
+	lcd_shift_control(DISPLAY_SHIFT | direction);
+}
+
+void write_to_lcd(uint8_t byte, uint8_t mode)
+{
+	switch (mode) {
+		case LCD_CMD:
+			bcm2835_gpio_clr(LCD_RS);
+			// fprintf(stdout, "Set RS to cmd mode\n");
+			break;
+		case LCD_DATA:
+			bcm2835_gpio_set(LCD_RS);
+			// fprintf(stdout, "Set RS to data mode for '%c'\n", byte);
+			break;
+		default:
+			// fprintf(stderr, "mode for setting GPIO pin unknown: %i\n", mode);
+			exit(EXIT_FAILURE);
+	}
+
+	// write high bits
+	bcm2835_gpio_clr(LCD_D4);
+	bcm2835_gpio_clr(LCD_D5);
+	bcm2835_gpio_clr(LCD_D6);
+	bcm2835_gpio_clr(LCD_D7);
+
+	if ((byte & 0x10) == 0x10) {
+		bcm2835_gpio_set(LCD_D4);
+	}
+	if ((byte & 0x20) == 0x20) {
+		bcm2835_gpio_set(LCD_D5);
+	}
+	if ((byte & 0x40) == 0x40) {
+		bcm2835_gpio_set(LCD_D6);
+	}
+	if ((byte & 0x80) == 0x80) {
+		bcm2835_gpio_set(LCD_D7);
+	}
+
+	// Toogle ENABLE pin in us
+	pulse_e();
+
+	// write low bits
+	bcm2835_gpio_clr(LCD_D4);
+	bcm2835_gpio_clr(LCD_D5);
+	bcm2835_gpio_clr(LCD_D6);
+	bcm2835_gpio_clr(LCD_D7);
+
+	if ((byte & 0x01) == 0x01) {
+		bcm2835_gpio_set(LCD_D4);
+	}
+	if ((byte & 0x02) == 0x02) {
+		bcm2835_gpio_set(LCD_D5);
+	}
+	if ((byte & 0x04) == 0x04) {
+		bcm2835_gpio_set(LCD_D6);
+	}
+	if ((byte & 0x08) == 0x08) {
+		bcm2835_gpio_set(LCD_D7);
+	}
+
+	pulse_e();
+
+}
+
+void write_string(char *str)
+{
+	uint16_t i;
+	uint8_t len = 0;
+
+	len = (strlen(str) > LCD_WIDTH ? LCD_WIDTH : strlen(str));
+
+	for (i=0; i<len;i++) {
+		write_to_lcd(str[i], LCD_DATA);
+	}
+}
+
+uint8_t read_from_lcd(uint8_t mode)
+{
+	// FIXME: this function currently does not work!
+	// Assuming, the display is driven by 5V
+	// then the GPIO Ports on a Raspberry Pi
+	// would get 5V what definitly is too much
+	uint8_t addr = 0x00;
+
+	bcm2835_gpio_clr(LCD_E);
+
+	bcm2835_gpio_clr(LCD_D4);
+	bcm2835_gpio_clr(LCD_D5);
+	bcm2835_gpio_clr(LCD_D6);
+	bcm2835_gpio_clr(LCD_D7);
+
+	switch (mode) {
+		case LCD_CMD:
+			bcm2835_gpio_clr(LCD_RS);
+			// fprintf(stdout, "Set RS to cmd mode\n");
+			break;
+		case LCD_DATA:
+			bcm2835_gpio_set(LCD_RS);
+			// fprintf(stdout, "Set RS to data mode for '%c'\n", byte);
+			break;
+		default:
+			// fprintf(stderr, "mode for setting GPIO pin unknown: %i\n", mode);
+			exit(EXIT_FAILURE);
+	}
+
+	set_data_pins_to_input();
+	bcm2835_delay(5);
+
+	bcm2835_gpio_set(LCD_RW);
+
+	pulse_e();
+
+	// read high bits
+	if (bcm2835_gpio_lev(LCD_D4))
+		addr = (addr | 0x10);
+	if (bcm2835_gpio_lev(LCD_D5))
+		addr = (addr | 0x20);
+	if (bcm2835_gpio_lev(LCD_D6))
+		addr = (addr | 0x40);
+	if (bcm2835_gpio_lev(LCD_D7))
+		addr = (addr | 0x80);
+
+	// Toogle ENABLE pin in us
+	pulse_e();
+
+	// read low bits
+	if (bcm2835_gpio_lev(LCD_D4))
+		addr = (addr | 0x01);
+	if (bcm2835_gpio_lev(LCD_D5))
+		addr = (addr | 0x02);
+	if (bcm2835_gpio_lev(LCD_D6))
+		addr = (addr | 0x04);
+	if (bcm2835_gpio_lev(LCD_D7))
+		addr = (addr | 0x08);
+
+	bcm2835_gpio_clr(LCD_RW);
+
+	set_data_pins_to_output();
+
+	return addr;
+}
+
+void gpio_reset(void)
+{
+	// bcm2835_gpio_fsel(LCD_RS, BCM2835_GPIO_PUD_OFF);
+	// bcm2835_gpio_fsel(LCD_E, BCM2835_GPIO_PUD_OFF);
+	// bcm2835_gpio_fsel(LCD_D4, BCM2835_GPIO_PUD_OFF);
+	// bcm2835_gpio_fsel(LCD_D5, BCM2835_GPIO_PUD_OFF);
+	// bcm2835_gpio_fsel(LCD_D6, BCM2835_GPIO_PUD_OFF);
+	// bcm2835_gpio_fsel(LCD_D7, BCM2835_GPIO_PUD_OFF);
+
+	// bcm2835_gpio_fsel(LCD_RS, BCM2835_GPIO_FSEL_INPT);
+	// bcm2835_gpio_fsel(LCD_E, BCM2835_GPIO_FSEL_INPT);
+	// bcm2835_gpio_fsel(LCD_D4, BCM2835_GPIO_FSEL_INPT);
+	// bcm2835_gpio_fsel(LCD_D5, BCM2835_GPIO_FSEL_INPT);
+	// bcm2835_gpio_fsel(LCD_D6, BCM2835_GPIO_FSEL_INPT);
+	// bcm2835_gpio_fsel(LCD_D7, BCM2835_GPIO_FSEL_INPT);
+
+	bcm2835_gpio_clr(LCD_RS);
+	bcm2835_gpio_clr(LCD_RW);
+	bcm2835_gpio_clr(LCD_E);
+	bcm2835_gpio_clr(LCD_D4);
+	bcm2835_gpio_clr(LCD_D5);
+	bcm2835_gpio_clr(LCD_D6);
+	bcm2835_gpio_clr(LCD_D7);
+}