beagle_hd44780.c file to include to interface lcd into beaglebone black

#include "beagle_hd44780.h"

/**
 * @brief Converts a character in two bitstreams the LCD can understand.
 * @param character The character we want to write.
 * @param part This can be either 0 or 1. Part 0 correspond to DB7..DB4,
 * while part 1 corresponds to DB3..DB0 on 8 bit mode. Since we are doing
 * 4 bit mode, we need to split the bitstream in two parts.
 **/
unsigned int write_character (char character, int part)
{
assert(part==0 || part==1);

char acB[2];
sprintf(acB, "%x", character);

unsigned int return_value = 0;

switch (acB[part])
{
case '0': return_value = 16; break;
case '1': return_value = 24; break;
case '2': return_value = 20; break;
case '3': return_value = 28; break;
case '4': return_value = 18; break;
case '5': return_value = 26; break;
case '6': return_value = 22; break;
case '7': return_value = 30; break;
case '8': return_value = 17; break;
case '9': return_value = 25; break;
case 'a': return_value = 21; break;
case 'b': return_value = 29; break;
case 'c': return_value = 19; break;
case 'd': return_value = 27; break;
case 'e': return_value = 23; break;
case 'f': return_value = 31; break;
}

return(return_value);
}

/**
 * @brief Puts a single character onto the screen.
 * @param characterToWrite The character we want to write.
 * @param selected_GPIOs[] initialized array of gpioID.
 **/
void charToScreen(char characterToWrite, struct gpioID enabled_gpio[])
{
unsigned int data_to_write=0;
const char *pinDescription[] = {"","","","","",""};

data_to_write=write_character (characterToWrite,0);
turn_ON_OFF_pins(enabled_gpio,data_to_write,6,0.10,pinDescription);
pulsePin(enabled_gpio,data_to_write,6,0, pinDescription, 5, 0.10);
  sleep(0.10);

data_to_write=write_character (characterToWrite,1);
turn_ON_OFF_pins(enabled_gpio,data_to_write,6,0.10,pinDescription);
pulsePin(enabled_gpio,data_to_write,6,0, pinDescription, 5, 0.10);
  sleep(0.10);

}
/**
 * @brief Initializes the screen so we can use it.
 * @param selected_GPIOs[] An initialized array of gpioID.
 * @param selectedPins[] The user defined pins.
 **/
void initialize_Screen(struct gpioID enabled_gpio[],int selectedPins[])
{
int nbr_selectedPins=6;
const char *pinDescription[] = {"","","","","",""};
unsigned int data_to_write;

initialize_each_enabled_gpio(enabled_gpio,selectedPins,nbr_selectedPins);
if (DISPLAY_DATA_ON_SCREEN) display_each_enabled_gpio(enabled_gpio,nbr_selectedPins,pinDescription);

//E RS DB4 DB5 DB6 DB7
//0 0  1   1   0   0 (base 2) which equals 12 (base 10)
    data_to_write=12;
turn_ON_OFF_pins(enabled_gpio,data_to_write,nbr_selectedPins,MAX_DELAY,pinDescription);
pulsePin(enabled_gpio,data_to_write,nbr_selectedPins,DISPLAY_DATA_ON_SCREEN, pinDescription, 5, MAX_DELAY);
  sleep(MAX_DELAY);

//E RS DB4 DB5 DB6 DB7
//0 0  0   1   0   0 (base 2) which equals 4 (base 10) : 4 bit mode
    data_to_write=4;
turn_ON_OFF_pins(enabled_gpio,data_to_write,nbr_selectedPins,MAX_DELAY,pinDescription);
pulsePin(enabled_gpio,data_to_write,nbr_selectedPins,DISPLAY_DATA_ON_SCREEN, pinDescription, 5, MAX_DELAY);
  sleep(MAX_DELAY);

//enable display part 1 - Display ON/OFF & Cursor
//E RS DB4 DB5 DB6 DB7 = 000000 (2) == 0 (10)
    data_to_write=0;
turn_ON_OFF_pins(enabled_gpio,data_to_write,nbr_selectedPins,MAX_DELAY,pinDescription);
pulsePin(enabled_gpio,data_to_write,nbr_selectedPins,DISPLAY_DATA_ON_SCREEN, pinDescription, 5, MAX_DELAY);
  sleep(MAX_DELAY);

//enable display part 2 - Display ON/OFF & Cursor
//E RS DB4 DB5 DB6 DB7 = 000011 (2) == 3 (10)
    data_to_write=3;
turn_ON_OFF_pins(enabled_gpio,data_to_write,nbr_selectedPins,MAX_DELAY,pinDescription);
pulsePin(enabled_gpio,data_to_write,nbr_selectedPins,DISPLAY_DATA_ON_SCREEN, pinDescription, 5, MAX_DELAY);
  sleep(MAX_DELAY);
 
  //two line mode 5x7 part 1
//E RS DB4 DB5 DB6 DB7 = 000100 (2) == 4  (10)
    data_to_write=4;
turn_ON_OFF_pins(enabled_gpio,data_to_write,nbr_selectedPins,MAX_DELAY,pinDescription);
pulsePin(enabled_gpio,data_to_write,nbr_selectedPins,DISPLAY_DATA_ON_SCREEN, pinDescription, 5, MAX_DELAY);
  sleep(MAX_DELAY);

  //two line mode 5x7 part 2 (the 0 next to the 1 specifies the 5x7)
//E RS DB4 DB5 DB6 DB7 = 000001 (2) == 1 (10)
    data_to_write=1;
turn_ON_OFF_pins(enabled_gpio,data_to_write,nbr_selectedPins,MAX_DELAY,pinDescription);
pulsePin(enabled_gpio,data_to_write,nbr_selectedPins,DISPLAY_DATA_ON_SCREEN, pinDescription, 5, MAX_DELAY);
  sleep(MAX_DELAY);

}

/**
 * @brief Enables the blinking cursor with an underline.
 * @param selected_GPIOs[] initialized array of gpioID.
 **/
void enableBlinkingCursor(struct gpioID enabled_gpio[])
{
int nbr_selectedPins=6;
const char *pinDescription[] = {"","","","","",""};
unsigned int data_to_write;

//enable cursor part 1
//E RS DB4 DB5 DB6 DB7 = 000000 (2) == 0 (10)
    data_to_write=0;
turn_ON_OFF_pins(enabled_gpio,data_to_write,nbr_selectedPins,MAX_DELAY,pinDescription);
pulsePin(enabled_gpio,data_to_write,nbr_selectedPins,DISPLAY_DATA_ON_SCREEN, pinDescription, 5, MAX_DELAY);
  sleep(MAX_DELAY);

//enable cursor part 2
//E RS DB4 DB5 DB6 DB7 = 001111 (2) == 15 (10)
    data_to_write=15;
turn_ON_OFF_pins(enabled_gpio,data_to_write,nbr_selectedPins,MAX_DELAY,pinDescription);
pulsePin(enabled_gpio,data_to_write,nbr_selectedPins,DISPLAY_DATA_ON_SCREEN, pinDescription, 5, MAX_DELAY);
  sleep(MAX_DELAY);
}

/**
 * @brief Disables the blinking cursor with an underline.
 * @param selected_GPIOs[] initialized array of gpioID.
 **/
void disableBlinkingCursor(struct gpioID enabled_gpio[])
{
int nbr_selectedPins=6;
const char *pinDescription[] = {"","","","","",""};
unsigned int data_to_write;

//enable cursor part 1
//E RS DB4 DB5 DB6 DB7 = 000000 (2) == 0 (10)
    data_to_write=0;
turn_ON_OFF_pins(enabled_gpio,data_to_write,nbr_selectedPins,MAX_DELAY,pinDescription);
pulsePin(enabled_gpio,data_to_write,nbr_selectedPins,DISPLAY_DATA_ON_SCREEN, pinDescription, 5, MAX_DELAY);
  sleep(MAX_DELAY);

//enable display part 2 - Display ON/OFF & Cursor
//E RS DB4 DB5 DB6 DB7 = 000011 (2) == 3 (10)
    data_to_write=3;
turn_ON_OFF_pins(enabled_gpio,data_to_write,nbr_selectedPins,MAX_DELAY,pinDescription);
pulsePin(enabled_gpio,data_to_write,nbr_selectedPins,DISPLAY_DATA_ON_SCREEN, pinDescription, 5, MAX_DELAY);
  sleep(MAX_DELAY);
}

/**
 * @brief Clears the LCD from anything thats in there.
 * @param selected_GPIOs[] initialized array of gpioID.
 **/
void clear_Screen(struct gpioID enabled_gpio[])
{
int nbr_selectedPins=6;
const char *pinDescription[] = {"","","","","",""};
unsigned int data_to_write;

//E RS DB4 DB5 DB6 DB7 = 000000 (2) == 0 (10)
data_to_write=0;
turn_ON_OFF_pins(enabled_gpio,data_to_write,nbr_selectedPins,MAX_DELAY,pinDescription);
pulsePin(enabled_gpio,data_to_write,nbr_selectedPins,DISPLAY_DATA_ON_SCREEN, pinDescription, 5, MAX_DELAY);
  sleep(MAX_DELAY);

//E RS DB4 DB5 DB6 DB7 = 001000 (2) == 8 (10)
data_to_write=8;
turn_ON_OFF_pins(enabled_gpio,data_to_write,nbr_selectedPins,MAX_DELAY,pinDescription);
pulsePin(enabled_gpio,data_to_write,nbr_selectedPins,DISPLAY_DATA_ON_SCREEN, pinDescription, 5, MAX_DELAY);
  sleep(MAX_DELAY);
}


/**
 * @brief After you are done using the LCD you should terminate it properly.
 * Failure to do so will guarantee that next time you use LCD it will be on 8 bit
 * mode... and you will must turn ON/OFF the screen.
 * @param selected_GPIOs[] initialized array of gpioID.
 **/
void terminate_Screen(struct gpioID enabled_gpio[],int selectedPins[])
{
int nbr_selectedPins=6;
const char *pinDescription[] = {"","","","","",""};
unsigned int data_to_write;

//put the display back in 8 bit mode to allow to re-run program
//E RS DB4 DB5 DB6 DB7 = 001100 (2) == 12 (10)
data_to_write=12;
turn_ON_OFF_pins(enabled_gpio,data_to_write,nbr_selectedPins,MAX_DELAY,pinDescription);
pulsePin(enabled_gpio,data_to_write,nbr_selectedPins,DISPLAY_DATA_ON_SCREEN, pinDescription, 5, MAX_DELAY);
  sleep(MAX_DELAY);

  //we should now tell the OS that we are done with the GPIOs
cleanup_GPIO(enabled_gpio,selectedPins,nbr_selectedPins);
}

/**
 * @brief Prints a string to the screen.
 * @param full_string  String that needs to be printed on the LCD
 * @param selected_GPIOs[] Initialized array of gpioID.
 **/
void stringToScreen(const char *full_string, struct gpioID enabled_gpio[])
{
int i;
int length = strlen(full_string);

for (i=0; i<length; i++)
{
charToScreen(full_string[i],enabled_gpio);
//printf("%c\n",full_string[i]);
}
}

/**
 * @brief Sets the cursor to either the first or second line.
 * @param line If line==0, cursor will be placed on top line. If line==1, the
 * the cursor will be placed on the bottom line.
 * @param selected_GPIOs[] initialized array of gpioID.
 **/
void goto_ScreenLine(int line, struct gpioID enabled_gpio[])
{
assert(line==0 || line==1);
goto_ScreenLocation(line,0,enabled_gpio);
}

/**
 * @brief This function is still not working correctly. Technically the
 * function should set the cursor to a well defined position in the LCD, but
 * it is not doing so for the second line. I think my LCD is broken. Until, I
 * fix this function (or at least test it with different LCDs) do not use it.
 * @param line Line number; where 0 is the top line and 1 is the bottom line.
 * @param position Position; where the initial position is 0.
 * @param selected_GPIOs[] Initialized array of gpioID.
 **/
void goto_ScreenLocation(int line, int position,struct gpioID enabled_gpio[])
{
int nbr_selectedPins=6;
const char *pinDescription[] = {"","","","","",""};
unsigned int data_to_write;

//printf("position: %d\n",position);
//printf("line: %d\n\n",line);

if (line==1) position=position+40;
data_to_write=return_address_in_bitform(position,0);
//printf("data_to_write: %d\n",data_to_write);
data_to_write=bitWrite(data_to_write,1,0);
//printf("<%d>\n",data_to_write);
turn_ON_OFF_pins(enabled_gpio,data_to_write,nbr_selectedPins,MAX_DELAY,pinDescription);
pulsePin(enabled_gpio,data_to_write,nbr_selectedPins,DISPLAY_DATA_ON_SCREEN, pinDescription, 5, MAX_DELAY);
  sleep(MAX_DELAY);

data_to_write=return_address_in_bitform(position,1);
//printf("data_to_write: %d\n",data_to_write);
turn_ON_OFF_pins(enabled_gpio,data_to_write,nbr_selectedPins,MAX_DELAY,pinDescription);
pulsePin(enabled_gpio,data_to_write,nbr_selectedPins,DISPLAY_DATA_ON_SCREEN, pinDescription, 5, MAX_DELAY);
  sleep(MAX_DELAY);
}

/**
 * @brief Returns the address in a split format such that we can send it to
   the screen position functions.
 * @param address This is the position we want to set the cursor to.
 * @param part This can be either 0 or 1. Part 0 correspond to DB7..DB4,
 * @param selected_GPIOs[] Initialized array of gpioID.
 **/

unsigned int return_address_in_bitform (unsigned int address, int part)
{
assert(part==0 || part==1);

unsigned int return_value=0;

if (part==1)
{
return_value=bitWrite(return_value,bitRead(address,3),0);
return_value=bitWrite(return_value,bitRead(address,2),1);
return_value=bitWrite(return_value,bitRead(address,1),2);
return_value=bitWrite(return_value,bitRead(address,0),3);
}

if (part==0)
{
return_value=bitWrite(return_value,bitRead(address,4),3);
return_value=bitWrite(return_value,bitRead(address,5),2);
return_value=bitWrite(return_value,bitRead(address,6),1);
return_value=bitWrite(return_value,bitRead(address,7),0);
}

return(return_value);
}