lcd2004.cpp

00001 #include "mbed.h"
00002 #include "lcd2004.h"
00003 
00004 // commands
00005 #define LCD_CLEARDISPLAY 0x01
00006 #define LCD_RETURNHOME 0x02
00007 #define LCD_ENTRYMODESET 0x04
00008 #define LCD_DISPLAYCONTROL 0x08
00009 #define LCD_CURSORSHIFT 0x10
00010 #define LCD_FUNCTIONSET 0x20
00011 #define LCD_SETCGRAMADDR 0x40
00012 #define LCD_SETDDRAMADDR 0x80
00013 
00014 // flags for display entry mode
00015 #define LCD_ENTRYRIGHT 0x00
00016 #define LCD_ENTRYLEFT 0x02
00017 #define LCD_ENTRYSHIFTINCREMENT 0x01
00018 #define LCD_ENTRYSHIFTDECREMENT 0x00
00019 
00020 // flags for display on/off control
00021 #define LCD_DISPLAY 0x04
00022 #define LCD_CURSOR 0x02
00023 #define LCD_BLINK 0x01
00024 
00025 // flags for display/cursor shift
00026 #define LCD_DISPLAYMOVE 0x08
00027 #define LCD_CURSORMOVE 0x00
00028 #define LCD_MOVERIGHT 0x04
00029 #define LCD_MOVELEFT 0x00
00030 
00031 #define ADDR     0x4E
00032 #define PIN_E    1<<2
00033 #define PIN_RW   1<<1
00034 #define PIN_RS   1<<0
00035 #define PIN_D4   1<<4
00036 #define PIN_D5   1<<5
00037 #define PIN_D6   1<<6
00038 #define PIN_D7   1<<7
00039 #define PIN_BL   1<<3
00040 
00041 Serial cPC(SERIAL_TX, SERIAL_RX);
00042 
00043 const uint8_t k_aMapper[] =
00044 {
00045     PIN_D4,
00046     PIN_D5,
00047     PIN_D6,
00048     PIN_D7,
00049 };
00050 
00051 LCD2004::LCD2004(I2C & in_cI2C)
00052     : LCD(in_cI2C)
00053     , m_nDisplayControl(LCD_DISPLAY)
00054 {
00055     ::wait_ms(100);    
00056     write_reg(PIN_D5 | PIN_D4);
00057     ::wait_ms(5);
00058     write_reg(PIN_D5 | PIN_D4);
00059     ::wait_us(100);
00060     write_reg(PIN_D5 | PIN_D4);
00061     
00062     // IV
00063     write_reg(PIN_D5);
00064     write_reg(PIN_D5);
00065     write_reg(PIN_D7);
00066     write_reg(0);
00067     write_reg(PIN_D7);
00068     write_reg(0);
00069     write_reg(PIN_D4);
00070     write_reg(0);
00071     write_reg(PIN_D7 | PIN_D6 /* | PIN_D5 | PIN_D4 */); // D5 = cursor on D4 = BLINK
00072 }
00073 
00074 int LCD2004::_putc(int in_nValue)
00075 {
00076     write_data(PIN_RS, in_nValue);    
00077     return 0;
00078 }
00079 
00080 void LCD2004::clear()
00081 {
00082     write_data(0, LCD_CLEARDISPLAY);
00083 }
00084 
00085 uint8_t LCD2004::columns()
00086 {
00087     return 20;
00088 }
00089 
00090 void LCD2004::createChar(uint8_t location, uint8_t charmap[])
00091 {
00092     location &= 0x7; // we only have 8 locations 0-7
00093     write_data(0, LCD_SETCGRAMADDR | (location << 3));
00094     
00095     for (int i=0; i<8; i++)
00096     {
00097         _putc(charmap[i]);
00098     }
00099     
00100     write_data(0, LCD_SETDDRAMADDR);  // unfortunately resets the location to 0,0
00101 }
00102 
00103 void LCD2004::home()
00104 {
00105     write_data(0, LCD_RETURNHOME);
00106 }
00107 
00108 uint8_t LCD2004::read_reg(void)
00109 {
00110     char nData = PIN_RW | PIN_BL;
00111     m_cI2C.write(ADDR,&nData,1);
00112     
00113     nData = PIN_RW | PIN_BL | PIN_E;
00114     m_cI2C.write(ADDR,&nData,1);
00115 
00116     ::wait_ms(0.05);
00117 
00118     char nValue = 0;    
00119     m_cI2C.read(ADDR,&nValue,1);
00120 
00121     nData = PIN_RW | PIN_BL;
00122     m_cI2C.write(ADDR,&nData,1);
00123     
00124     ::wait_ms(0.05);
00125     
00126     return nValue & (PIN_D7 | PIN_D6 | PIN_D5 | PIN_D4);
00127 }
00128 
00129 uint8_t LCD2004::remap(uint8_t in_nValue)
00130 {
00131     uint8_t nValue = 0;
00132     for (size_t i = 0; i < 4; i++)
00133     {
00134         if (in_nValue & (1 << i)) nValue |= k_aMapper[i];
00135     }
00136     
00137     return nValue;
00138 }
00139 
00140 uint8_t LCD2004::rows()
00141 {
00142     return 4;
00143 }
00144 
00145 void LCD2004::setCursor(uint8_t in_nX, uint8_t in_nY)
00146 {
00147     int row_offsets[] = { 0x00, 0x40, 0x14, 0x54 };
00148 
00149     // D7 = Set DDRAM address
00150     uint8_t nValue = LCD_SETDDRAMADDR | (in_nX + row_offsets[in_nY]);
00151     write_data(0, nValue);
00152 }
00153 
00154 void LCD2004::setDisplayControl(uint8_t in_nReg, bool in_bEnable)
00155 {
00156     uint8_t nDisplayControl = m_nDisplayControl;
00157     
00158     if (in_bEnable)
00159     {
00160         m_nDisplayControl |= in_nReg;
00161     }
00162     else
00163     {
00164         m_nDisplayControl &= ~in_nReg;
00165     }
00166 
00167     if (nDisplayControl != m_nDisplayControl)
00168     {
00169         write_data(0,LCD_DISPLAYCONTROL | m_nDisplayControl);
00170     }
00171 }
00172 
00173 void LCD2004::showBlink(bool in_bShow)
00174 {
00175     setDisplayControl(LCD_BLINK,in_bShow);
00176 }
00177 
00178 void LCD2004::showCursor(bool in_bShow)
00179 {
00180     setDisplayControl(LCD_CURSOR, in_bShow);
00181 }
00182 
00183 void LCD2004::showDisplay(bool in_bShow)
00184 {
00185     setDisplayControl(LCD_DISPLAY,in_bShow);
00186 }
00187 
00188 void LCD2004::write_data(uint8_t in_nReg, uint8_t in_nValue)
00189 {
00190     write_reg(in_nReg | remap(in_nValue >> 4));
00191     write_reg(in_nReg | remap(in_nValue & 0x0F));    
00192 }
00193 
00194 void LCD2004::write_reg(uint8_t in_nValue)
00195 {
00196     char nData = PIN_E | PIN_BL | in_nValue;
00197     m_cI2C.write(ADDR,&nData,1);
00198         
00199     ::wait_us(1450);
00200     
00201     nData = PIN_BL | in_nValue;
00202     m_cI2C.write(ADDR,&nData,1);    
00203 }