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+/*
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+ * lcd.c:
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+ * Text-based LCD driver.
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+ * This is designed to drive the parallel interface LCD drivers
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+ * based in the Hitachi HD44780U controller and compatables.
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+ *
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+ * Copyright (c) 2012 Gordon Henderson.
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+ ***********************************************************************
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+ * This file is part of wiringPi:
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+ * https://projects.drogon.net/raspberry-pi/wiringpi/
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+ *
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+ * wiringPi is free software: you can redistribute it and/or modify
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+ * it under the terms of the GNU Lesser General Public License as published by
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+ * the Free Software Foundation, either version 3 of the License, or
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+ * (at your option) any later version.
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+ *
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+ * wiringPi is distributed in the hope that it will be useful,
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+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
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+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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+ * GNU Lesser General Public License for more details.
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+ *
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+ * You should have received a copy of the GNU Lesser General Public License
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+ * along with wiringPi. If not, see <http://www.gnu.org/licenses/>.
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+ ***********************************************************************
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+ */
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+
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+#include <stdio.h>
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+#include <stdlib.h>
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+#include <stdarg.h>
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+
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+#include <wiringPi.h>
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+
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+#include "spi.h"
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+#include "lcd.h"
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+
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+#ifndef TRUE
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+# define TRUE (1==1)
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+# define FALSE (1==2)
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+#endif
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+
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+// HD44780U Commands
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+
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+#define LCD_CLEAR 0x01
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+#define LCD_HOME 0x02
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+#define LCD_ENTRY 0x04
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+#define LCD_CTRL 0x08
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+#define LCD_CDSHIFT 0x10
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+#define LCD_FUNC 0x20
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+#define LCD_CGRAM 0x40
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+#define LCD_DGRAM 0x80
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+
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+// Bits in the entry register
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+
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+#define LCD_ENTRY_SH 0x01
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+#define LCD_ENTRY_ID 0x02
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+
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+// Bits in the control register
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+
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+#define LCD_BLINK_CTRL 0x01
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+#define LCD_CURSOR_CTRL 0x02
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+#define LCD_DISPLAY_CTRL 0x04
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+
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+// Bits in the function register
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+
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+#define LCD_FUNC_F 0x04
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+#define LCD_FUNC_N 0x08
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+#define LCD_FUNC_DL 0x10
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+
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+#define LCD_CDSHIFT_RL 0x04
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+
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+struct lcdDataStruct {
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+ int bits, rows, cols;
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+ int rsPin, strbPin;
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+ int cx, cy;
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+};
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+
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+struct lcdDataStruct *lcds[MAX_LCDS];
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+
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+static int lcdControl;
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+
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+// Row offsets
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+
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+static const int rowOff[4] = { 0x00, 0x40, 0x14, 0x54 };
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+
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+/*
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+ * strobe:
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+ * Toggle the strobe (Really the "E") pin to the device.
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+ * According to the docs, data is latched on the falling edge.
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+ *********************************************************************************
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+ */
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+
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+static void strobe(const struct lcdDataStruct *lcd) {
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+
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+// Note timing changes for new version of delayMicroseconds ()
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+
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+ digitalWrite(lcd->strbPin, 1);
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+ delayMicroseconds(50);
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+ digitalWrite(lcd->strbPin, 0);
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+ delayMicroseconds(50);
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+}
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+
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+/*
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+ * sentDataCmd:
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+ * Send an data or command byte to the display.
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+ *********************************************************************************
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+ */
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+
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+static void sendDataCmd(const struct lcdDataStruct *lcd, unsigned char data) {
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+ register unsigned char myData = data;
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+ unsigned char i, d4;
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+
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+ if (lcd->bits == 4) {
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+ d4 = (myData >> 4) & 0x0F;
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+ shift_data(d4);
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+ d4 >>= 4;
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+ strobe(lcd);
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+
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+ d4 = myData & 0x0F;
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+ shift_data(d4);
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+ } else {
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+ shift_data(myData);
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+ }
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+ strobe(lcd);
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+}
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+
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+/*
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+ * putCommand:
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+ * Send a command byte to the display
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+ *********************************************************************************
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+ */
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+
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+static void putCommand(const struct lcdDataStruct *lcd, unsigned char command) {
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+ digitalWrite(lcd->rsPin, 0);
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+ sendDataCmd(lcd, command);
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+ delay(2);
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+}
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+
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+static void put4Command(const struct lcdDataStruct *lcd,
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+ unsigned char command) {
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+ register unsigned char myCommand = command;
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+ register unsigned char i;
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+
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+ digitalWrite(lcd->rsPin, 0);
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+ shift_data(command & 0x0F);
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+ strobe(lcd);
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+}
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+
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+/*
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+ *********************************************************************************
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+ * User Callable code below here
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+ *********************************************************************************
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+ */
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+
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+/*
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+ * lcdHome: lcdClear:
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+ * Home the cursor or clear the screen.
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+ *********************************************************************************
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+ */
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+
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+void lcdHome(const int fd) {
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+ struct lcdDataStruct *lcd = lcds[fd];
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+
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+ putCommand(lcd, LCD_HOME);
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+ lcd->cx = lcd->cy = 0;
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+ delay(5);
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+}
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+
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+void lcdClear(const int fd) {
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+ struct lcdDataStruct *lcd = lcds[fd];
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+
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+ putCommand(lcd, LCD_CLEAR);
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+ putCommand(lcd, LCD_HOME);
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+ lcd->cx = lcd->cy = 0;
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+ delay(5);
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+}
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+
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+/*
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+ * lcdDisplay: lcdCursor: lcdCursorBlink:
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+ * Turn the display, cursor, cursor blinking on/off
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+ *********************************************************************************
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+ */
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+
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+void lcdDisplay(const int fd, int state) {
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+ struct lcdDataStruct *lcd = lcds[fd];
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+
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+ if (state)
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+ lcdControl |= LCD_DISPLAY_CTRL;
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+ else
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+ lcdControl &= ~LCD_DISPLAY_CTRL;
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+
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+ putCommand(lcd, LCD_CTRL | lcdControl);
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+}
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+
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+void lcdCursor(const int fd, int state) {
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+ struct lcdDataStruct *lcd = lcds[fd];
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+
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+ if (state)
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+ lcdControl |= LCD_CURSOR_CTRL;
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+ else
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+ lcdControl &= ~LCD_CURSOR_CTRL;
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+
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+ putCommand(lcd, LCD_CTRL | lcdControl);
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+}
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+
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+void lcdCursorBlink(const int fd, int state) {
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+ struct lcdDataStruct *lcd = lcds[fd];
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+
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+ if (state)
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+ lcdControl |= LCD_BLINK_CTRL;
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+ else
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+ lcdControl &= ~LCD_BLINK_CTRL;
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+
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+ putCommand(lcd, LCD_CTRL | lcdControl);
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+}
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+
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+/*
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+ * lcdSendCommand:
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+ * Send any arbitary command to the display
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+ *********************************************************************************
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+ */
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+
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+void lcdSendCommand(const int fd, unsigned char command) {
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+ struct lcdDataStruct *lcd = lcds[fd];
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+ putCommand(lcd, command);
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+}
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+
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+/*
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+ * lcdPosition:
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+ * Update the position of the cursor on the display.
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+ * Ignore invalid locations.
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+ *********************************************************************************
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+ */
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+
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+void lcdPosition(const int fd, int x, int y) {
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+ struct lcdDataStruct *lcd = lcds[fd];
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+
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+ if ((x > lcd->cols) || (x < 0))
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+ return;
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+ if ((y > lcd->rows) || (y < 0))
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+ return;
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+
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+ putCommand(lcd, x + (LCD_DGRAM | rowOff[y]));
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+
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+ lcd->cx = x;
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+ lcd->cy = y;
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+}
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+
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+/*
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+ * lcdCharDef:
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+ * Defines a new character in the CGRAM
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+ *********************************************************************************
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+ */
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+
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+void lcdCharDef(const int fd, int index, unsigned char data[8]) {
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+ struct lcdDataStruct *lcd = lcds[fd];
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+ int i;
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+
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+ putCommand(lcd, LCD_CGRAM | ((index & 7) << 3));
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+
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+ digitalWrite(lcd->rsPin, 1);
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+ for (i = 0; i < 8; ++i)
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+ sendDataCmd(lcd, data[i]);
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+}
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+
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+/*
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+ * lcdPutchar:
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+ * Send a data byte to be displayed on the display. We implement a very
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+ * simple terminal here - with line wrapping, but no scrolling. Yet.
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+ *********************************************************************************
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+ */
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+
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+void lcdPutchar(const int fd, unsigned char data) {
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+ struct lcdDataStruct *lcd = lcds[fd];
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+
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+ digitalWrite(lcd->rsPin, 1);
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+ sendDataCmd(lcd, data);
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+
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+ if (++lcd->cx == lcd->cols) {
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+ lcd->cx = 0;
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+ if (++lcd->cy == lcd->rows)
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+ lcd->cy = 0;
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+
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+ putCommand(lcd, lcd->cx + (LCD_DGRAM | rowOff[lcd->cy]));
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+ }
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+}
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+
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+/*
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+ * lcdPuts:
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+ * Send a string to be displayed on the display
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+ *********************************************************************************
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+ */
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+
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+void lcdPuts(const int fd, const char *string) {
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+ while (*string)
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+ lcdPutchar(fd, *string++);
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+}
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+
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+/*
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+ * lcdPrintf:
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+ * Printf to an LCD display
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+ *********************************************************************************
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+ */
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+
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+void lcdPrintf(const int fd, const char *message, ...) {
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+ va_list argp;
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+ char buffer[1024];
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+
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+ va_start (argp, message);
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+ vsnprintf(buffer, 1023, message, argp);
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+ va_end (argp);
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+
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+ lcdPuts(fd, buffer);
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+}
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+
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+/*
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+ * lcdInit:
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+ * directly initialises the LCD for the CoffeePi
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+ *********************************************************************************
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+ */
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+
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+int lcdInit(void) {
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+ spi_init();
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+ shift_init();
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+ pinMode(LCD_RW, OUTPUT);
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+ digitalWrite(LCD_RW, LOW);
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+ return lcdInitI(2, 16, 8, LCD_RS, LCD_EN);
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+}
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+
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+/*
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+ * lcdInit:
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+ * Take a lot of parameters and initialise the LCD, and return a handle to
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+ * that LCD, or -1 if any error.
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+ *********************************************************************************
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+ */
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+
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+int lcdInitI(const int rows, const int cols, const int bits, const int rs,
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+ const int strb) {
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+ static int initialised = 0;
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+
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+ unsigned char func;
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+ int i;
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+ int lcdFd = -1;
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+ struct lcdDataStruct *lcd;
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+
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+ if (initialised == 0) {
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+ initialised = 1;
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+ for (i = 0; i < MAX_LCDS; ++i)
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+ lcds[i] = NULL;
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+ }
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+
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+// Simple sanity checks
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+
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+ if (!((bits == 4) || (bits == 8)))
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+ return -1;
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+
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+ if ((rows < 0) || (rows > 20))
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+ return -1;
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+
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+ if ((cols < 0) || (cols > 20))
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+ return -1;
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+
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+// Create a new LCD:
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+
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+ for (i = 0; i < MAX_LCDS; ++i) {
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+ if (lcds[i] == NULL) {
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+ lcdFd = i;
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+ break;
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+ }
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+ }
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+
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+ if (lcdFd == -1)
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+ return -1;
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+
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+ lcd = (struct lcdDataStruct *) malloc(sizeof(struct lcdDataStruct));
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+ if (lcd == NULL)
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+ return -1;
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+
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+ lcd->rsPin = rs;
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+ lcd->strbPin = strb;
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+ lcd->bits = 8; // For now - we'll set it properly later.
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+ lcd->rows = rows;
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+ lcd->cols = cols;
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+ lcd->cx = 0;
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+ lcd->cy = 0;
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+
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+ lcds[lcdFd] = lcd;
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+
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+ digitalWrite(lcd->rsPin, 0);
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+ pinMode(lcd->rsPin, OUTPUT);
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+ digitalWrite(lcd->strbPin, 0);
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+ pinMode(lcd->strbPin, OUTPUT);
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+
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+ delay(35); // mS
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+
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+// 4-bit mode?
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+// OK. This is a PIG and it's not at all obvious from the documentation I had,
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+// so I guess some others have worked through either with better documentation
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+// or more trial and error... Anyway here goes:
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+//
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+// It seems that the controller needs to see the FUNC command at least 3 times
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+// consecutively - in 8-bit mode. If you're only using 8-bit mode, then it appears
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+// that you can get away with one func-set, however I'd not rely on it...
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+//
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+// So to set 4-bit mode, you need to send the commands one nibble at a time,
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+// the same three times, but send the command to set it into 8-bit mode those
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+// three times, then send a final 4th command to set it into 4-bit mode, and only
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+// then can you flip the switch for the rest of the library to work in 4-bit
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+// mode which sends the commands as 2 x 4-bit values.
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+
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+ if (bits == 4) {
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+ func = LCD_FUNC | LCD_FUNC_DL; // Set 8-bit mode 3 times
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+ put4Command(lcd, func >> 4);
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+ delay(35);
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+ put4Command(lcd, func >> 4);
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+ delay(35);
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+ put4Command(lcd, func >> 4);
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+ delay(35);
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+ func = LCD_FUNC; // 4th set: 4-bit mode
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+ put4Command(lcd, func >> 4);
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+ delay(35);
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+ lcd->bits = 4;
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+ } else {
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+ func = LCD_FUNC | LCD_FUNC_DL;
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+ putCommand(lcd, func);
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+ delay(35);
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+ putCommand(lcd, func);
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+ delay(35);
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+ putCommand(lcd, func);
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+ delay(35);
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+ }
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+
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+ if (lcd->rows > 1) {
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+ func |= LCD_FUNC_N;
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+ putCommand(lcd, func);
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+ delay(35);
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+ }
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+
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+// Rest of the initialisation sequence
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+
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+ lcdDisplay(lcdFd, TRUE);
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+ lcdCursor(lcdFd, FALSE);
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+ lcdCursorBlink(lcdFd, FALSE);
|
|
|
+ lcdClear(lcdFd);
|
|
|
+
|
|
|
+ putCommand(lcd, LCD_ENTRY | LCD_ENTRY_ID);
|
|
|
+ putCommand(lcd, LCD_CDSHIFT | LCD_CDSHIFT_RL);
|
|
|
+
|
|
|
+ return lcdFd;
|
|
|
+}
|