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/* $Id: memtest.hh,v 1.8 2008-06-24 10:03:41 sybreon Exp $

**

** VIRTUAL PERIPHERAL I/O LIBRARY

** Copyright (C) 2009 Shawn Tan <shawn.tan@aeste.net>

**

** This file is part of AEMB.

**

** AEMB 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.

**

** AEMB 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 AEMB.  If not, see <http://www.gnu.org/licenses/>.

*/

/*!

  Character LCD Interface Library

  @file

  Interface library for standard HH44780/SED1278 character LCD

  drivers. This library assumes a 4-bit hardware interface mode to

  reduce the lines and GPIO width.

  Routines modified from AVRLib by Pascal Stang.

 */

#include "vpioGpio.h"

#ifndef VPIO_LCD_H

#define VPIO_LCD_H

#define LCD_NIB 1 // nibble mode

#define WAIT_STATE 1

// GPIO control lines - DO NOT MODIFY

#define LCD_D7 7 // D7 - P14

#define LCD_D6 6 // D6 - P13

#define LCD_D5 5 // D5 - P12

#define LCD_D4 4 // D4 - P11

#define LCD_EN 3 // EN - P6

#define LCD_RW 2 // RW - P5

#define LCD_RS 1 // RS - P4

#define LCD_HB 0 // HB - NC

// HD44780 LCD controller command set (do not modify these)

// writing:

#define LCD_CLR             0      // DB0: clear display

#define LCD_HOME            1      // DB1: return to home position

#define LCD_ENTRY_MODE      2      // DB2: set entry mode

#define LCD_ENTRY_INC       1      //   DB1: increment

#define LCD_ENTRY_SHIFT     0      //   DB2: shift

#define LCD_ON_CTRL         3      // DB3: turn lcd/cursor on

#define LCD_ON_DISPLAY      2      //   DB2: turn display on

#define LCD_ON_CURSOR       1      //   DB1: turn cursor on

#define LCD_ON_BLINK        0      //   DB0: blinking cursor

#define LCD_MOVE            4      // DB4: move cursor/display

#define LCD_MOVE_DISP       3      //   DB3: move display (0-> move cursor)

#define LCD_MOVE_RIGHT      2      //   DB2: move right (0-> left)

#define LCD_FUNCTION        5      // DB5: function set

#define LCD_FUNCTION_8BIT   4      //   DB4: set 8BIT mode (0->4BIT mode)

#define LCD_FUNCTION_2LINES 3      //   DB3: two lines (0->one line)

#define LCD_FUNCTION_10DOTS 2      //   DB2: 5x10 font (0->5x7 font)

#define LCD_CGRAM           6      // DB6: set CG RAM address

#define LCD_DDRAM           7      // DB7: set DD RAM address

// reading:

#define LCD_BUSY            7      // DB7: LCD is busy

// Default LCD setup

// this default setup is loaded on LCD initialization

#define LCD_FDEF_1           (0<<LCD_FUNCTION_8BIT)

#define LCD_FDEF_2           (1<<LCD_FUNCTION_2LINES)

#define LCD_FUNCTION_DEFAULT ((1<<LCD_FUNCTION) | LCD_FDEF_1 | LCD_FDEF_2)

#define LCD_MODE_DEFAULT     ((1<<LCD_ENTRY_MODE) | (1<<LCD_ENTRY_INC))

#define LCD_OUTPUT  0xFF

#define LCD_INPUT   0x0F

typedef struct gpioRegs lcdRegs;

// Low-level I/O functions

void lcdReset(lcdRegs* lcd);

void lcdWaitBusy(lcdRegs* lcd);

void lcdPutControl(lcdRegs* lcd, char ctrl);

char lcdGetControl(lcdRegs* lcd);

void lcdPutData(lcdRegs* lcd, char data);

char lcdGetData(lcdRegs* lcd);

void lcdDelay(int ms);

//void lcdSetTris(lcdRegs* lcd, gpioTrisType dir);

// High-level application functions

void lcdInit(lcdRegs* lcd);

void lcdHome(lcdRegs* lcd);

void lcdClear(lcdRegs* lcd);

/*!

  Reset the LCD hardware.

  @param lcd LCD GPIO port.

 */

void lcdReset(lcdRegs* lcd)

{

  // set GPIO to output

  gpioSetTris(lcd, LCD_OUTPUT);

  // clear lines

  /*

  gpioClrBit(lcd, LCD_RS);

  gpioClrBit(lcd, LCD_RW);

  gpioClrBit(lcd, LCD_EN);

  */

  gpioPutData(lcd, 0x00);

  // set lines

  /*

  gpioSetBit(lcd, LCD_RS);

  gpioSetBit(lcd, LCD_RW);

  gpioSetBit(lcd, LCD_EN);

  */

  gpioPutData(lcd, 0xFF);

  // set GPIO to input

  gpioSetTris(lcd, LCD_INPUT);

}

/*!

  Blocking wait for LCD busy signal.

  This function blocks the LCD port while the busy signal is asserted

  by the LCD.

  @param lcd LCD GPIO port.

 */

void lcdWaitBusy(lcdRegs* lcd)

{

  int i;

  gpioSetTris(lcd, LCD_INPUT); // set INPUT

  //gpioClrBit(lcd, LCD_RS); // select CONTROL

  //gpioSetBit(lcd, LCD_RW); // set to READ

  //gpioSetBit(lcd, LCD_EN);

  gpioPutData(lcd, (1<<LCD_RW) | (1<<LCD_EN)); // EN|RD|CT

  lcdDelay(WAIT_STATE);

  while (gpioGetBit(lcd, LCD_BUSY))

    {

      for (i = 2; i>0; --i)

        {

          /*

            gpioClrBit(lcd, LCD_EN);

            lcdDelay(WAIT_STATE);

            gpioSetBit(lcd, LCD_EN);

            lcdDelay(WAIT_STATE);

          */

          gpioPutData(lcd, (1<<LCD_RW) );

          lcdDelay(WAIT_STATE);

          gpioPutData(lcd, (1<<LCD_RW) | (1<<LCD_EN) );

          lcdDelay(WAIT_STATE);

        }

    }

  gpioPutData(lcd, (1<<LCD_RW) );

  //gpioClrBit(lcd, LCD_EN);

  //gpioTogBit(lcd, LCD_HB);

}

/*!

  Write a control byte to the LCD.

  This function writes a byte to the LCD control register.

  @param lcd LCD GPIO port.

  @param ctrl Control byte to write

 */

void lcdPutControl(lcdRegs* lcd, char ctrl)

{

  lcdWaitBusy(lcd); // wait until free

  //gpioClrBit(lcd, LCD_RS); // select CONTROL

  //gpioClrBit(lcd, LCD_RW); // set to WRITE

  gpioPutData(lcd, (1<<LCD_HB));

  gpioSetTris(lcd, LCD_OUTPUT); // Set OUTPUT

  gpioPutData(lcd, (gpioGetData(lcd) & 0x0F) | (ctrl & 0xF0) );

  gpioSetBit(lcd, LCD_EN);

  lcdDelay(WAIT_STATE);

  gpioClrBit(lcd, LCD_EN);

  lcdDelay(WAIT_STATE);

  gpioPutData(lcd, (gpioGetData(lcd) & 0x0F) | (ctrl << 4) );

  gpioSetBit(lcd, LCD_EN);

  lcdDelay(WAIT_STATE);

  gpioClrBit(lcd, LCD_EN);

  gpioSetTris(lcd, LCD_INPUT); // set INPUT

}

/*!

  Read a control byte from the LCD.

  This function reads a control byte from the LCD control register.

  @param lcd LCD GPIO port.

  @return control register value.

 */

char lcdGetControl(lcdRegs* lcd)

{

  char b;

  lcdWaitBusy(lcd); // wait until free

  gpioSetTris(lcd, LCD_INPUT); // Set INPUT

  //gpioClrBit(lcd, LCD_RS); // select CONTROL

  //gpioSetBit(lcd, LCD_RW); // set to READ

  //gpioSetBit(lcd, LCD_EN); 

  gpioPutData(lcd, (1<<LCD_RW) | (1<<LCD_EN) );

  lcdDelay(WAIT_STATE);

  b = gpioGetData(lcd) & 0xF0; // read upper nib

  gpioClrBit(lcd, LCD_EN);

  lcdDelay(WAIT_STATE);

  gpioSetBit(lcd, LCD_EN);

  lcdDelay(WAIT_STATE);

  gpioClrBit(lcd, LCD_EN);

  b |= (gpioGetData(lcd) >> 4); // read lower nib

  gpioSetTris(lcd, LCD_INPUT); // set INPUT

  return b;

}

/*!

  Write a data byte to the LCD.

  This function writes a byte to the LCD data register.

  @param lcd LCD GPIO port.

  @param ctrl Control byte to write

 */

void lcdPutData(lcdRegs* lcd, char data)

{

  lcdWaitBusy(lcd); // wait until free

  //gpioSetBit(lcd, LCD_RS); // select DATA

  //gpioClrBit(lcd, LCD_RW); // set to WRITE

  gpioPutData(lcd, (1<<LCD_RS) );

  gpioSetTris(lcd, LCD_OUTPUT); // Set OUTPUT

  gpioPutData(lcd, (gpioGetData(lcd) & 0x0F) | (data & 0xF0) );

  gpioSetBit(lcd, LCD_EN);

  lcdDelay(WAIT_STATE);

  gpioClrBit(lcd, LCD_EN);

  lcdDelay(WAIT_STATE);

  gpioPutData(lcd, (gpioGetData(lcd) & 0x0F) | (data << 4) );

  gpioSetBit(lcd, LCD_EN);

  lcdDelay(WAIT_STATE);

  gpioClrBit(lcd, LCD_EN);

  //gpioPutData(lcd, (1<<LCD_RS) );

  gpioSetTris(lcd, LCD_INPUT); // set INPUT

}

/*!

  Read a data byte from the LCD.

  This function reads a control byte from the LCD control register.

  @param lcd LCD GPIO port.

  @return data register value.

 */

char lcdGetData(lcdRegs* lcd)

{

  char b;

  lcdWaitBusy(lcd); // wait until free

  gpioSetTris(lcd, LCD_INPUT); // Set INPUT

  gpioSetBit(lcd, LCD_RS); // select DATA

  gpioSetBit(lcd, LCD_RW); // set to READ

  gpioSetBit(lcd, LCD_EN);

  lcdDelay(WAIT_STATE);

  b = gpioGetData(lcd) & 0xF0; // read upper nib

  gpioClrBit(lcd, LCD_EN);

  lcdDelay(WAIT_STATE);

  gpioSetBit(lcd, LCD_EN);

  lcdDelay(WAIT_STATE);

  gpioClrBit(lcd, LCD_EN);

  b |= (gpioGetData(lcd) >> 4); // read lower nib

  gpioSetTris(lcd, LCD_INPUT); // set INPUT

  return b;

}

/*!

  Initialisation Routine.

  This function brings the LCD through the standard initialisation

  process. It sets the LCD mode to default entry modes, clears the

  screen and cursors to home.

  @param lcd LCD GPIO port.

 */

void lcdInit(lcdRegs* lcd)

{

  lcdReset(lcd); // reset HW

  lcdPutControl(lcd, LCD_FUNCTION_DEFAULT);

  lcdPutControl(lcd, 1 << LCD_CLR);

  lcdDelay(0x00008000); // delay 30ms+

  lcdPutControl(lcd, 1 << LCD_ENTRY_MODE | 1 << LCD_ENTRY_INC);

  lcdPutControl(lcd, 1 << LCD_ON_CTRL | 1 << LCD_ON_DISPLAY);

  lcdPutControl(lcd, 1 << LCD_HOME);

  lcdPutControl(lcd, 1 << LCD_DDRAM | 0x00);

}

/*!

  Arbitrary delay routine.

  This function does a NOP loop for an arbitrary number of cycles. The

  cycles are not calibrated to any clock but is assumed to run on a

  nominal 100MHz clock.

  @param us Assume number of micro-seconds (us).

 */

inline

void lcdDelay(int us)

{

  int i;

  //for (i = 0; i < (ms << 3); ++i) { asm volatile ("nop"); } // do NOP

  for (i = us << 4; i > 0; --i) { asm volatile ("nop"); } // do NOP

}

/*!

  Returns the LCD cursor to home.

  @param lcd LCD GPIO port.

 */

void lcdHome(lcdRegs* lcd)

{

  lcdPutControl(lcd, 1<<LCD_HOME);

}

/*!

  Clear the LCD screen.

  @param lcd LCD GPIO port.

 */

void lcdClear(lcdRegs* lcd)

{

  lcdPutControl(lcd, 1<<LCD_CLR);

}

#endif