peripherals: add LCD lib [#2]

source/shoh/src/peripherals/LiquidCrystal.cpp

@@ -0,0 +1,289 @@
+#include "LiquidCrystal.h"
+
+#include <cstring>
+#include "chip.h"
+
+#define LOW 0
+#define HIGH 1
+
+
+#if 0
+void delayMicroseconds(unsigned int us)
+{
+	// implement with RIT
+}
+#else
+void delayMicroseconds(uint32_t delay)
+{
+	static int init;
+	if(!init) {
+		// start core clock counter
+		CoreDebug->DEMCR |= 1 << 24;
+		DWT->CTRL |= 1;
+		init = 1;
+	}
+
+	uint32_t start = DWT->CYCCNT;
+	delay = delay * 72; // assuming 72MHz clock
+	while(DWT->CYCCNT - start < delay);
+}
+
+#endif
+
+// When the display powers up, it is configured as follows:
+//
+// 1. Display clear
+// 2. Function set:
+//    DL = 1; 8-bit interface data
+//    N = 0; 1-line display
+//    F = 0; 5x8 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
+//
+// Note, however, that resetting the Arduino doesn't reset the LCD, so we
+// can't assume that its in that state when a sketch starts (and the
+// LiquidCrystal constructor is called).
+
+
+
+LiquidCrystal::LiquidCrystal(DigitalIoPin *rs,  DigitalIoPin *enable,
+			     DigitalIoPin *d0, DigitalIoPin *d1, DigitalIoPin *d2, DigitalIoPin *d3)
+{
+  rs_pin = rs;
+  enable_pin = enable;
+
+  data_pins[0] = d0;
+  data_pins[1] = d1;
+  data_pins[2] = d2;
+  data_pins[3] = d3;
+
+  _displayfunction = LCD_4BITMODE | LCD_1LINE | LCD_5x8DOTS;
+
+  begin(16, 2); // default to 16x2 display
+}
+
+void LiquidCrystal::begin(uint8_t cols, uint8_t lines, uint8_t dotsize) {
+  if (lines > 1) {
+    _displayfunction |= LCD_2LINE;
+  }
+  _numlines = lines;
+  _currline = 0;
+
+  // for some 1 line displays you can select a 10 pixel high font
+  if ((dotsize != 0) && (lines == 1)) {
+    _displayfunction |= LCD_5x10DOTS;
+  }
+
+  // SEE PAGE 45/46 FOR INITIALIZATION SPECIFICATION!
+  // according to datasheet, we need at least 40ms after power rises above 2.7V
+  // before sending commands. Arduino can turn on way befer 4.5V so we'll wait 50
+  delayMicroseconds(50000);
+  // Now we pull both RS and R/W low to begin commands
+  rs_pin->write(false); //digitalWrite(_rs_pin, LOW);
+  enable_pin->write(false); //digitalWrite(_enable_pin, LOW);
+
+  // note: this port supports only 4 bit mode
+  //put the LCD into 4 bit or 8 bit mode
+  if (! (_displayfunction & LCD_8BITMODE)) {
+    // this is according to the hitachi HD44780 datasheet
+    // figure 24, pg 46
+
+    // we start in 8bit mode, try to set 4 bit mode
+    write4bits(0x03);
+    delayMicroseconds(4500); // wait min 4.1ms
+
+    // second try
+    write4bits(0x03);
+    delayMicroseconds(4500); // wait min 4.1ms
+
+    // third go!
+    write4bits(0x03);
+    delayMicroseconds(150);
+
+    // finally, set to 4-bit interface
+    write4bits(0x02);
+  } else {
+    // this is according to the hitachi HD44780 datasheet
+    // page 45 figure 23
+
+    // Send function set command sequence
+    command(LCD_FUNCTIONSET | _displayfunction);
+    delayMicroseconds(4500);  // wait more than 4.1ms
+
+    // second try
+    command(LCD_FUNCTIONSET | _displayfunction);
+    delayMicroseconds(150);
+
+    // third go
+    command(LCD_FUNCTIONSET | _displayfunction);
+  }
+
+  // finally, set # lines, font size, etc.
+  command(LCD_FUNCTIONSET | _displayfunction);
+
+  // turn the display on with no cursor or blinking default
+  _displaycontrol = LCD_DISPLAYON | LCD_CURSOROFF | LCD_BLINKOFF;
+  display();
+
+  // clear it off
+  clear();
+
+  // Initialize to default text direction (for romance languages)
+  _displaymode = LCD_ENTRYLEFT | LCD_ENTRYSHIFTDECREMENT;
+  // set the entry mode
+  command(LCD_ENTRYMODESET | _displaymode);
+
+}
+
+/********** high level commands, for the user! */
+void LiquidCrystal::clear()
+{
+  command(LCD_CLEARDISPLAY);  // clear display, set cursor position to zero
+  delayMicroseconds(2000);  // this command takes a long time!
+}
+
+void LiquidCrystal::home()
+{
+  command(LCD_RETURNHOME);  // set cursor position to zero
+  delayMicroseconds(2000);  // this command takes a long time!
+}
+
+
+void LiquidCrystal::print(std::string const &s)
+{
+	print(s.c_str());
+}
+
+void LiquidCrystal::print(const char *s)
+{
+	while(*s) {
+		write(*s);
+		++s;
+	}
+}
+
+void LiquidCrystal::setCursor(uint8_t col, uint8_t row)
+{
+  int row_offsets[] = { 0x00, 0x40, 0x14, 0x54 };
+  if ( row >= _numlines ) {
+    row = _numlines-1;    // we count rows starting w/0
+  }
+
+  command(LCD_SETDDRAMADDR | (col + row_offsets[row]));
+}
+
+// Turn the display on/off (quickly)
+void LiquidCrystal::noDisplay() {
+  _displaycontrol &= ~LCD_DISPLAYON;
+  command(LCD_DISPLAYCONTROL | _displaycontrol);
+}
+void LiquidCrystal::display() {
+  _displaycontrol |= LCD_DISPLAYON;
+  command(LCD_DISPLAYCONTROL | _displaycontrol);
+}
+
+// Turns the underline cursor on/off
+void LiquidCrystal::noCursor() {
+  _displaycontrol &= ~LCD_CURSORON;
+  command(LCD_DISPLAYCONTROL | _displaycontrol);
+}
+void LiquidCrystal::cursor() {
+  _displaycontrol |= LCD_CURSORON;
+  command(LCD_DISPLAYCONTROL | _displaycontrol);
+}
+
+// Turn on and off the blinking cursor
+void LiquidCrystal::noBlink() {
+  _displaycontrol &= ~LCD_BLINKON;
+  command(LCD_DISPLAYCONTROL | _displaycontrol);
+}
+void LiquidCrystal::blink() {
+  _displaycontrol |= LCD_BLINKON;
+  command(LCD_DISPLAYCONTROL | _displaycontrol);
+}
+
+// These commands scroll the display without changing the RAM
+void LiquidCrystal::scrollDisplayLeft(void) {
+  command(LCD_CURSORSHIFT | LCD_DISPLAYMOVE | LCD_MOVELEFT);
+}
+void LiquidCrystal::scrollDisplayRight(void) {
+  command(LCD_CURSORSHIFT | LCD_DISPLAYMOVE | LCD_MOVERIGHT);
+}
+
+// This is for text that flows Left to Right
+void LiquidCrystal::leftToRight(void) {
+  _displaymode |= LCD_ENTRYLEFT;
+  command(LCD_ENTRYMODESET | _displaymode);
+}
+
+// This is for text that flows Right to Left
+void LiquidCrystal::rightToLeft(void) {
+  _displaymode &= ~LCD_ENTRYLEFT;
+  command(LCD_ENTRYMODESET | _displaymode);
+}
+
+// This will 'right justify' text from the cursor
+void LiquidCrystal::autoscroll(void) {
+  _displaymode |= LCD_ENTRYSHIFTINCREMENT;
+  command(LCD_ENTRYMODESET | _displaymode);
+}
+
+// This will 'left justify' text from the cursor
+void LiquidCrystal::noAutoscroll(void) {
+  _displaymode &= ~LCD_ENTRYSHIFTINCREMENT;
+  command(LCD_ENTRYMODESET | _displaymode);
+}
+
+// Allows us to fill the first 8 CGRAM locations
+// with custom characters
+void LiquidCrystal::createChar(uint8_t location, uint8_t charmap[]) {
+  location &= 0x7; // we only have 8 locations 0-7
+  command(LCD_SETCGRAMADDR | (location << 3));
+  for (int i=0; i<8; i++) {
+    write(charmap[i]);
+  }
+}
+
+/*********** mid level commands, for sending data/cmds */
+
+inline void LiquidCrystal::command(uint8_t value) {
+  send(value, LOW);
+}
+
+inline size_t LiquidCrystal::write(uint8_t value) {
+  send(value, HIGH);
+  return 1; // assume sucess
+}
+
+/************ low level data pushing commands **********/
+
+// write either command or data
+void LiquidCrystal::send(uint8_t value, uint8_t mode) {
+  rs_pin->write(mode); //digitalWrite(_rs_pin, mode);
+
+  write4bits(value>>4);
+  write4bits(value);
+}
+
+void LiquidCrystal::pulseEnable(void) {
+  enable_pin->write(false); //digitalWrite(_enable_pin, LOW);
+  delayMicroseconds(1);
+  enable_pin->write(true); //digitalWrite(_enable_pin, HIGH);
+  delayMicroseconds(1);    // enable pulse must be >450ns
+  enable_pin->write(false); //digitalWrite(_enable_pin, LOW);
+  delayMicroseconds(100);   // commands need > 37us to settle
+}
+
+void LiquidCrystal::write4bits(uint8_t value) {
+  for (int i = 0; i < 4; i++) {
+    data_pins[i]->write((value >> i) & 0x01); //digitalWrite(_data_pins[i], (value >> i) & 0x01);
+  }
+
+  pulseEnable();
+}
+

source/shoh/src/peripherals/LiquidCrystal.h

@@ -0,0 +1,97 @@
+#ifndef LiquidCrystal_h
+#define LiquidCrystal_h
+
+
+#include <cstddef>
+#include <string>
+#include "chip.h"
+#include "DigitalIoPin.h"
+
+// commands
+#define LCD_CLEARDISPLAY 0x01
+#define LCD_RETURNHOME 0x02
+#define LCD_ENTRYMODESET 0x04
+#define LCD_DISPLAYCONTROL 0x08
+#define LCD_CURSORSHIFT 0x10
+#define LCD_FUNCTIONSET 0x20
+#define LCD_SETCGRAMADDR 0x40
+#define LCD_SETDDRAMADDR 0x80
+
+// flags for display entry mode
+#define LCD_ENTRYRIGHT 0x00
+#define LCD_ENTRYLEFT 0x02
+#define LCD_ENTRYSHIFTINCREMENT 0x01
+#define LCD_ENTRYSHIFTDECREMENT 0x00
+
+// flags for display on/off control
+#define LCD_DISPLAYON 0x04
+#define LCD_DISPLAYOFF 0x00
+#define LCD_CURSORON 0x02
+#define LCD_CURSOROFF 0x00
+#define LCD_BLINKON 0x01
+#define LCD_BLINKOFF 0x00
+
+// flags for display/cursor shift
+#define LCD_DISPLAYMOVE 0x08
+#define LCD_CURSORMOVE 0x00
+#define LCD_MOVERIGHT 0x04
+#define LCD_MOVELEFT 0x00
+
+// flags for function set
+#define LCD_8BITMODE 0x10
+#define LCD_4BITMODE 0x00
+#define LCD_2LINE 0x08
+#define LCD_1LINE 0x00
+#define LCD_5x10DOTS 0x04
+#define LCD_5x8DOTS 0x00
+
+class LiquidCrystal {
+public:
+
+  LiquidCrystal(DigitalIoPin *rs,  DigitalIoPin *enable,
+			    DigitalIoPin *d0, DigitalIoPin *d1, DigitalIoPin *d2, DigitalIoPin *d3);
+
+  void begin(uint8_t cols, uint8_t rows, uint8_t charsize = LCD_5x8DOTS);
+
+  void clear();
+  void home();
+
+  void noDisplay();
+  void display();
+  void noBlink();
+  void blink();
+  void noCursor();
+  void cursor();
+  void scrollDisplayLeft();
+  void scrollDisplayRight();
+  void leftToRight();
+  void rightToLeft();
+  void autoscroll();
+  void noAutoscroll();
+
+  void createChar(uint8_t, uint8_t[]);
+  void setCursor(uint8_t, uint8_t);
+  virtual size_t write(uint8_t);
+  void command(uint8_t);
+  void print(std::string const &s);
+  void print(const char *s);
+
+private:
+  void send(uint8_t, uint8_t);
+  void write4bits(uint8_t);
+  void pulseEnable();
+
+  DigitalIoPin *rs_pin; // LOW(false): command.  HIGH(true): character.
+  DigitalIoPin *enable_pin; // activated by a HIGH pulse.
+  DigitalIoPin *data_pins[4];
+
+  uint8_t _displayfunction;
+  uint8_t _displaycontrol;
+  uint8_t _displaymode;
+
+  uint8_t _initialized;
+
+  uint8_t _numlines,_currline;
+};
+
+#endif