Wim Huiskamp
Updated for more display types. Fixed memoryaddress confusion in address() method. Added new getAddress() method. Added support for UDCs, Backlight control and other features such as control through I2C and SPI port expanders and controllers with native I2C and SPI interfaces. Refactored to fix issue with pins that are default declared as NC.
Dependents: GPSDevice TestTextLCD SD to Flash Data Transfer DrumMachine ... more
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TextLCD
by 
Simon Ford
Example
Hello World! for the TextLCD
#include "mbed.h"
#include "TextLCD.h"
// Host PC Communication channels
Serial pc(USBTX, USBRX); // tx, rx
// I2C Communication
I2C i2c_lcd(p28,p27); // SDA, SCL
// SPI Communication
SPI spi_lcd(p5, NC, p7); // MOSI, MISO, SCLK
//TextLCD lcd(p15, p16, p17, p18, p19, p20); // RS, E, D4-D7, LCDType=LCD16x2, BL=NC, E2=NC, LCDTCtrl=HD44780
//TextLCD_SPI lcd(&spi_lcd, p8, TextLCD::LCD40x4); // SPI bus, 74595 expander, CS pin, LCD Type
TextLCD_I2C lcd(&i2c_lcd, 0x42, TextLCD::LCD20x4); // I2C bus, PCF8574 Slaveaddress, LCD Type
//TextLCD_I2C lcd(&i2c_lcd, 0x42, TextLCD::LCD16x2, TextLCD::WS0010); // I2C bus, PCF8574 Slaveaddress, LCD Type, Device Type
//TextLCD_SPI_N lcd(&spi_lcd, p8, p9); // SPI bus, CS pin, RS pin, LCDType=LCD16x2, BL=NC, LCDTCtrl=ST7032_3V3
//TextLCD_I2C_N lcd(&i2c_lcd, ST7032_SA, TextLCD::LCD16x2, NC, TextLCD::ST7032_3V3); // I2C bus, Slaveaddress, LCD Type, BL=NC, LCDTCtrl=ST7032_3V3
int main() {
pc.printf("LCD Test. Columns=%d, Rows=%d\n\r", lcd.columns(), lcd.rows());
for (int row=0; row<lcd.rows(); row++) {
int col=0;
pc.printf("MemAddr(Col=%d, Row=%d)=0x%02X\n\r", col, row, lcd.getAddress(col, row));
// lcd.putc('-');
lcd.putc('0' + row);
for (col=1; col<lcd.columns()-1; col++) {
lcd.putc('*');
}
pc.printf("MemAddr(Col=%d, Row=%d)=0x%02X\n\r", col, row, lcd.getAddress(col, row));
lcd.putc('+');
}
// Show cursor as blinking character
lcd.setCursor(TextLCD::CurOff_BlkOn);
// Set and show user defined characters. A maximum of 8 UDCs are supported by the HD44780.
// They are defined by a 5x7 bitpattern.
lcd.setUDC(0, (char *) udc_0); // Show |>
lcd.putc(0);
lcd.setUDC(1, (char *) udc_1); // Show <|
lcd.putc(1);
}
Handbook page
More info is here
Diff: TextLCD.cpp
- Revision:
- 13:24506ba22480
- Parent:
- 12:6bf9d9957d31
- Child:
- 14:0c32b66b14b8
--- a/TextLCD.cpp Tue Feb 05 21:50:43 2013 +0000
+++ b/TextLCD.cpp Sat Feb 09 15:10:36 2013 +0000
@@ -24,90 +24,127 @@
#include "TextLCD.h"
#include "mbed.h"
-TextLCD::TextLCD(PinName rs, PinName e, PinName d4, PinName d5,
- PinName d6, PinName d7, LCDType type) : _rs(rs),
- _e(e), _d(d4, d5, d6, d7),
+TextLCD::TextLCD(PinName rs, PinName e,
+ PinName d4, PinName d5, PinName d6, PinName d7,
+ LCDType type): _rs(rs), _e(e),
+ _d(d4, d5, d6, d7),
+ _type(type) {
+
+
+ _busType = _PinBus;
+
+ _init();
+
+}
+
+
+TextLCD::TextLCD(I2C *i2c, char deviceAddress, LCDType type) :
+ _rs(NC), _e(NC), _d(NC),
+ _i2c(i2c),
_type(type) {
+
+ _slaveAddress = deviceAddress;
+ _busType = _I2CBus;
- _e = 1;
- _rs = 0; // command mode
+
+ // Init the portexpander bus
+ _lcd_bus = 0x80;
+
+ // write the new data to the portexpander
+ _i2c->write(_slaveAddress, &_lcd_bus, 1);
+
+ _init();
+
+}
+/** Init the LCD controller
+ * 4-bit mode, number of lines, no cursor etc
+ * Clear display
+ */
+void TextLCD::_init() {
+// _e = 1;
+// _rs = 0; // command mode
+
+ _setEnable(true);
+ _setRS(false); // command mode
+
wait(0.015); // Wait 15ms to ensure powered up
// send "Display Settings" 3 times (Only top nibble of 0x30 as we've got 4-bit bus)
for (int i=0; i<3; i++) {
- writeByte(0x3);
+ _writeByte(0x3);
wait(0.00164); // this command takes 1.64ms, so wait for it
}
- writeByte(0x2); // 4-bit mode
- wait(0.000040f); // most instructions take 40us
+ _writeByte(0x2); // 4-bit mode
+ wait(0.000040f); // most instructions take 40us
// Display is now in 4-bit mode
switch (_type) {
case LCD8x1:
- writeCommand(0x20); // Function set 001 BW N F - -
- // N=0 (1 line)
- // F=0 (5x7 dots font)
+ _writeCommand(0x20); // Function set 001 BW N F - -
+ // N=0 (1 line)
+ // F=0 (5x7 dots font)
break;
case LCD24x4:
// Special mode for KS0078
- writeCommand(0x2A); // Function set 001 BW N RE DH REV
- // N=1 (Dont care for KS0078)
- // RE=0 (Extended Regs, special mode for KS0078)
- // DH=1 (Disp shift, special mode for KS0078)
- // REV=0 (Reverse, special mode for KS0078)
+ _writeCommand(0x2A); // Function set 001 BW N RE DH REV
+ // N=1 (Dont care for KS0078)
+ // RE=0 (Extended Regs, special mode for KS0078)
+ // DH=1 (Disp shift, special mode for KS0078)
+ // REV=0 (Reverse, special mode for KS0078)
- writeCommand(0x2E); // Function set 001 BW N RE DH REV
- // N=1 (Dont care for KS0078)
- // RE=1 (Ena Extended Regs, special mode for KS0078)
- // DH=1 (Disp shift, special mode for KS0078)
- // REV=0 (Reverse, special mode for KS0078)
+ _writeCommand(0x2E); // Function set 001 BW N RE DH REV
+ // N=1 (Dont care for KS0078)
+ // RE=1 (Ena Extended Regs, special mode for KS0078)
+ // DH=1 (Disp shift, special mode for KS0078)
+ // REV=0 (Reverse, special mode for KS0078)
- writeCommand(0x09); // Ext Function set 0000 1 FW BW NW
- // FW=0 (5-dot font, special mode for KS0078)
- // BW=0 (Cur BW invert disable, special mode for KS0078)
- // NW=1 (4 Line, special mode for KS0078)
+ _writeCommand(0x09); // Ext Function set 0000 1 FW BW NW
+ // FW=0 (5-dot font, special mode for KS0078)
+ // BW=0 (Cur BW invert disable, special mode for KS0078)
+ // NW=1 (4 Line, special mode for KS0078)
- writeCommand(0x2A); // Function set 001 BW N RE DH REV
- // N=1 (Dont care for KS0078)
- // RE=0 (Dis. Extended Regs, special mode for KS0078)
- // DH=1 (Disp shift, special mode for KS0078)
- // REV=0 (Reverse, special mode for KS0078)
+ _writeCommand(0x2A); // Function set 001 BW N RE DH REV
+ // N=1 (Dont care for KS0078)
+ // RE=0 (Dis. Extended Regs, special mode for KS0078)
+ // DH=1 (Disp shift, special mode for KS0078)
+ // REV=0 (Reverse, special mode for KS0078)
break;
default:
- writeCommand(0x28); // Function set 001 BW N F - -
- // N=1 (2 lines)
- // F=0 (5x7 dots font)
+ _writeCommand(0x28); // Function set 001 BW N F - -
+ // N=1 (2 lines)
+ // F=0 (5x7 dots font)
+ // - (Don't care)
break;
}
- writeCommand(0x06); // Entry Mode 0000 01 CD S
- // Cursor Direction and Display Shift
- // CD=1 (Cur incr)
- // S=0 (No display shift)
+ _writeCommand(0x06); // Entry Mode 0000 01 CD S
+ // Cursor Direction and Display Shift
+ // CD=1 (Cur incr)
+ // S=0 (No display shift)
-// writeCommand(0x0C); // Display Ctrl 0000 1 D C B
-// // Display On, Cursor Off, Blink Off
- cursor(TextLCD::CurOff_BlkOff);
+// _writeCommand(0x0C); // Display Ctrl 0000 1 D C B
+// // Display On, Cursor Off, Blink Off
+ setCursor(TextLCD::CurOff_BlkOff);
cls();
}
-void TextLCD::character(int column, int row, int c) {
+void TextLCD::_character(int column, int row, int c) {
int addr = getAddress(column, row);
- writeCommand(0x80 | addr);
- writeData(c);
+ _writeCommand(0x80 | addr);
+ _writeData(c);
}
void TextLCD::cls() {
- writeCommand(0x01); // cls, and set cursor to 0
- wait(0.00164f); // This command takes 1.64 ms
+ _writeCommand(0x01); // cls, and set cursor to 0
+ wait(0.00164f); // This command takes 1.64 ms
locate(0, 0);
}
@@ -124,7 +161,7 @@
_row = 0;
}
} else {
- character(_column, _row, value);
+ _character(_column, _row, value);
_column++;
if (_column >= columns()) {
_column = 0;
@@ -141,27 +178,135 @@
return -1;
}
-void TextLCD::writeByte(int value) {
- _d = value >> 4;
+
+void TextLCD::_setEnable(bool value) {
+
+ switch(_busType) {
+ case _PinBus :
+ if (value)
+ _e = 1; // Set E bit
+ else
+ _e = 0; // Reset E bit
+
+ break;
+
+ case _I2CBus :
+ if (value)
+ _lcd_bus |= D_LCD_E; // Set E bit
+ else
+ _lcd_bus &= ~D_LCD_E; // Reset E bit
+
+ // write the new data to the portexpander
+ _i2c->write(_slaveAddress, &_lcd_bus, 1);
+
+ break;
+
+ case _SPIBus :
+ break;
+ }
+}
+
+void TextLCD::_setRS(bool value) {
+
+ switch(_busType) {
+ case _PinBus :
+ if (value)
+ _rs = 1; // Set RS bit
+ else
+ _rs = 0; // Reset RS bit
+
+ break;
+
+ case _I2CBus :
+ if (value)
+ _lcd_bus |= D_LCD_RS; // Set RS bit
+ else
+ _lcd_bus &= ~D_LCD_RS; // Reset RS bit
+
+ // write the new data to the portexpander
+ _i2c->write(_slaveAddress, &_lcd_bus, 1);
+
+ break;
+
+ case _SPIBus :
+ break;
+ }
+
+}
+
+void TextLCD::_setData(int value) {
+ int data;
+
+ switch(_busType) {
+ case _PinBus :
+ _d = value & 0x0F; // Write Databits
+
+ break;
+
+ case _I2CBus :
+ data = value & 0x0F;
+ if (data & 0x01)
+ _lcd_bus |= D_LCD_D4; // Set Databit
+ else
+ _lcd_bus &= ~D_LCD_D4; // Reset Databit
+
+ if (data & 0x02)
+ _lcd_bus |= D_LCD_D5; // Set Databit
+ else
+ _lcd_bus &= ~D_LCD_D5; // Reset Databit
+
+ if (data & 0x04)
+ _lcd_bus |= D_LCD_D6; // Set Databit
+ else
+ _lcd_bus &= ~D_LCD_D6; // Reset Databit
+
+ if (data & 0x08)
+ _lcd_bus |= D_LCD_D7; // Set Databit
+ else
+ _lcd_bus &= ~D_LCD_D7; // Reset Databit
+
+ // write the new data to the portexpander
+ _i2c->write(_slaveAddress, &_lcd_bus, 1);
+
+ break;
+
+ case _SPIBus :
+ break;
+ }
+
+}
+
+
+
+void TextLCD::_writeByte(int value) {
+// _d = value >> 4;
+ _setData(value >> 4);
wait(0.000040f); // most instructions take 40us
- _e = 0;
+// _e = 0;
+ _setEnable(false);
wait(0.000040f);
- _e = 1;
- _d = value >> 0;
+// _e = 1;
+ _setEnable(true);
+// _d = value >> 0;
+ _setData(value >> 0);
wait(0.000040f);
- _e = 0;
+// _e = 0;
+ _setEnable(false);
wait(0.000040f); // most instructions take 40us
- _e = 1;
+// _e = 1;
+ _setEnable(true);
}
-void TextLCD::writeCommand(int command) {
- _rs = 0;
- writeByte(command);
+void TextLCD::_writeCommand(int command) {
+// _rs = 0;
+ _setRS(false);
+ _writeByte(command);
}
-void TextLCD::writeData(int data) {
- _rs = 1;
- writeByte(data);
+void TextLCD::_writeData(int data) {
+// _rs = 1;
+ _setRS(true);
+ _writeByte(data);
}
@@ -170,7 +315,7 @@
// It is confusing since it returns the memoryaddress or-ed with the set memorycommand 0x80.
// Left it in here for compatibility with older code. New applications should use getAddress() instead.
//
-int TextLCD::address(int column, int row) {
+int TextLCD::_address(int column, int row) {
switch (_type) {
case LCD20x4:
switch (row) {
@@ -196,7 +341,7 @@
// This replaces the original method.
// Left it in here for compatibility with older code. New applications should use getAddress() instead.
-int TextLCD::address(int column, int row) {
+int TextLCD::_address(int column, int row) {
return 0x80 | getAddress(column, row);
}
@@ -208,6 +353,13 @@
case LCD8x1:
return 0x00 + column;
+ case LCD16x1:
+ // LCD16x1 is a special layout of LCD8x2
+ if (column<8)
+ return 0x00 + column;
+ else
+ return 0x40 + (column - 8);
+
case LCD16x4:
switch (row) {
case 0:
@@ -263,7 +415,7 @@
}
-// Added for consistency. Set row, colum and update memoryaddress.
+// Added for consistency. Set row, column and update memoryaddress.
//
void TextLCD::setAddress(int column, int row) {
@@ -271,7 +423,7 @@
int addr = getAddress(column, row);
- writeCommand(0x80 | addr);
+ _writeCommand(0x80 | addr);
}
int TextLCD::columns() {
@@ -280,6 +432,7 @@
case LCD8x2:
return 8;
+ case LCD16x1:
case LCD16x2:
case LCD16x2B:
case LCD16x4:
@@ -305,6 +458,7 @@
int TextLCD::rows() {
switch (_type) {
case LCD8x1:
+ case LCD16x1:
return 1;
case LCD8x2:
@@ -327,25 +481,25 @@
}
-void TextLCD::cursor(TextLCD::LCDCursor show) {
+void TextLCD::setCursor(TextLCD::LCDCursor show) {
switch (show) {
- case CurOff_BlkOff : writeCommand(0x0C); // Cursor off and Blink Off
+ case CurOff_BlkOff : _writeCommand(0x0C); // Cursor off and Blink Off
wait_us(40);
_cursor = show;
break;
- case CurOn_BlkOff : writeCommand(0x0E); // Cursor on and Blink Off
+ case CurOn_BlkOff : _writeCommand(0x0E); // Cursor on and Blink Off
wait_us(40);
_cursor = show;
break;
- case CurOff_BlkOn : writeCommand(0x0D); // Cursor off and Blink On
+ case CurOff_BlkOn : _writeCommand(0x0D); // Cursor off and Blink On
wait_us(40);
_cursor = show;
break;
- case CurOn_BlkOn : writeCommand(0x0F); // Cursor on and Blink char
+ case CurOn_BlkOn : _writeCommand(0x0F); // Cursor on and Blink char
wait_us(40);
_cursor = show;
break;
@@ -360,10 +514,10 @@
void TextLCD::setUDC(unsigned char c, char *udc_data) {
- writeCommand(0x40 + ((c & 0x07) << 3)); //Set CG-RAM address
+ _writeCommand(0x40 + ((c & 0x07) << 3)); //Set CG-RAM address
for (int i=0; i<8; i++) {
- writeData(*udc_data++);
+ _writeData(*udc_data++);
}
}
HD44780 and compatible Text LCD controllers (4bit, I2C or SPI I/F)