commented library
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Lauchmelder23
parent
15307a468c
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355566a256
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@ -13,6 +13,7 @@ LCDScreen* configurePins(LCDScreen* screen, uint8_t RS, uint8_t RW, uint8_t E,
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uint8_t D0, uint8_t D1, uint8_t D2, uint8_t D3,
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uint8_t D4, uint8_t D5, uint8_t D6, uint8_t D7)
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{
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// Simply set all the fields to the supplied pins
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screen->RS = RS;
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screen->RW = RW;
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screen->E = E;
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@ -26,6 +27,7 @@ LCDScreen* configurePins(LCDScreen* screen, uint8_t RS, uint8_t RW, uint8_t E,
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screen->D6 = D6;
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screen->D7 = D7;
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// Initialize the pins to be output
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wiringPiSetup();
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pinMode(screen->RS, OUTPUT);
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pinMode(screen->RW, OUTPUT);
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@ -45,17 +47,25 @@ LCDScreen* configurePins(LCDScreen* screen, uint8_t RS, uint8_t RW, uint8_t E,
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void initScreen(LCDScreen* screen, uint8_t interface_bits, uint8_t num_lines, uint8_t fontType, uint8_t cursor, uint8_t writeDirection)
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{
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// Set interface bits of screen
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screen->interface_bits = interface_bits;
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sendCommand(screen, (FUNCTION_SET | HALF_BYTE_INTERFACE) >> 4);
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// Tell LCD screen to operate in intended bit mode
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sendCommand(screen, (FUNCTION_SET | interface_bits) >> 4);
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// Set number of display lines and font type
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sendCommand(screen, FUNCTION_SET | num_lines | fontType);
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// Turn display on and set cursor
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sendCommand(screen, DISPLAY_SWITCH | DISPLAY_ON | cursor);
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// Clear screen
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sendCommand(screen, SCREEN_CLEAR);
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// Set write direction
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sendCommand(screen, INPUT_SET | writeDirection);
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}
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void resetPins(LCDScreen* screen)
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{
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// Pull all pins low
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digitalWrite(screen->D7, LOW);
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digitalWrite(screen->D6, LOW);
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digitalWrite(screen->D5, LOW);
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@ -70,14 +80,20 @@ void resetPins(LCDScreen* screen)
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digitalWrite(screen->RS, LOW);
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}
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// A helper function to send bytes to the screen
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// This function is not visible to the user
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void helper_send(LCDScreen* screen, uint8_t byte)
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{
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// Pull Enable high
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digitalWrite(screen->E, HIGH);
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// Write high nibble
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digitalWrite(screen->D7, (byte >> 7) & 0x1);
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digitalWrite(screen->D6, (byte >> 6) & 0x1);
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digitalWrite(screen->D5, (byte >> 5) & 0x1);
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digitalWrite(screen->D4, (byte >> 4) & 0x1);
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// If we're in 8-bit mode, write the lower nibbles as well
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if(screen->interface_bits == FULL_BYTE_INTERFACE)
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{
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digitalWrite(screen->D3, (byte >> 3) & 0x1);
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@ -85,6 +101,7 @@ void helper_send(LCDScreen* screen, uint8_t byte)
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digitalWrite(screen->D1, (byte >> 1) & 0x1);
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digitalWrite(screen->D0, (byte >> 0) & 0x1);
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}
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// If in 4-bit, then send the high nibbles and then set the lower nibbles
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else if(screen->interface_bits == HALF_BYTE_INTERFACE)
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{
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delayMicroseconds(1000);
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@ -99,12 +116,14 @@ void helper_send(LCDScreen* screen, uint8_t byte)
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digitalWrite(screen->D4, (byte >> 0) & 0x1);
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}
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// Send the data supplied on the pins
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delayMicroseconds(1000);
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digitalWrite(screen->E, LOW);
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delayMicroseconds(10000);
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}
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// Sends a command by pulling RW and RS low
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void sendCommand(LCDScreen* screen, uint8_t command)
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{
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digitalWrite(screen->RW, LOW);
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@ -113,6 +132,7 @@ void sendCommand(LCDScreen* screen, uint8_t command)
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helper_send(screen, command);
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}
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// Sends a character by pulling only RW low
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void sendData(LCDScreen* screen, uint8_t data)
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{
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digitalWrite(screen->RW, LOW);
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@ -121,6 +141,7 @@ void sendData(LCDScreen* screen, uint8_t data)
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helper_send(screen, data);
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}
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// Loops over a char* and sends each character individually. Supports the katakana and math as well
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void sendText(LCDScreen* screen, const char* text)
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{
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for(const char* c = text; *c != '\x00'; c++)
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@ -234,6 +255,7 @@ void sendText(LCDScreen* screen, const char* text)
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}
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}
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// Sends a list of chars, similar to sendText
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void sendChars(LCDScreen* screen, size_t len, ...)
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{
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va_list args;
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@ -245,14 +267,19 @@ void sendChars(LCDScreen* screen, size_t len, ...)
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va_end(args);
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}
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// Loads a custom character into CGRAM
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void loadCustomChar(LCDScreen* screen, uint8_t cgram_addr, ...)
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{
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// Initialize va_args
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va_list args;
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va_start(args, cgram_addr);
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// Choose correct scram address
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sendCommand(screen, CGRAM_AD_SET | (cgram_addr << 3));
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// Write data to RAM
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for(int i = 0; i < 8; i++)
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sendData(screen, va_arg(args, int));
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// Free va_args
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va_end(args);
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}
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@ -133,33 +133,57 @@
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#include <stdint.h>
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#include <stdarg.h>
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// Just a wrapper for the delay() function from WiringPi
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extern void waitMs(uint32_t ms);
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// A struct containing the info about pin connections
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typedef struct {
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uint8_t RS, RW, E, D0, D1, D2, D3, D4, D5, D6, D7;
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uint8_t interface_bits;
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} LCDScreen;
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// Set the fields of LCDScreen to the according values. The user could also set them directly
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// without calling this function
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extern LCDScreen* configurePins(LCDScreen* screen, uint8_t RS, uint8_t RW, uint8_t E,
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uint8_t D0, uint8_t D1, uint8_t D2, uint8_t D3,
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uint8_t D4, uint8_t D5, uint8_t D6, uint8_t D7);
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// Performs the initialization sequence for the LCD screen
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extern void initScreen(LCDScreen* screen, uint8_t interface_bits, uint8_t num_lines, uint8_t fontType, uint8_t cursor, uint8_t writeDirection);
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// Pulls every pin low
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extern void resetPins(LCDScreen* screen);
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// Sends a command to the LCD screen
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extern void sendCommand(LCDScreen* screen, uint8_t command);
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// Sends a character to the LCD screen
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extern void sendData(LCDScreen* screen, uint8_t data);
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// Sends a string of text to the LCD screen
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extern void sendText(LCDScreen* screen, const char* text);
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// Sends a list of chars to the LCD screen
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extern void sendChars(LCDScreen* screen, unsigned int len, ...);
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// Writes a custom character into CGRAM
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extern void loadCustomChar(LCDScreen* screen, uint8_t cgram_addr, ...);
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// Clears the screen
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#define clearScreen(screen) sendCommand(screen, SCREEN_CLEAR)
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// Sets cursor to (0, 0)
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#define returnCursor(screen) sendCommand(screen, CURSOR_RETURN);
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// Sets the writing direction
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#define setWritingDirection(screen, direction) sendCommand(screen, INPUT_SET | direction)
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// Turns display on/off and changes cursor behaviour
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#define setDisplaySettings(screen, display, cursor_shown, cursor_behaviour) sendCommand(screen, DISPLAY_SWITCH | display | cursor_shown | cursor_behaviour)
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// Moves cursor by one cell to the left or right
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#define shiftCursor(screen, direction) sendCommand(screen, SHIFT | CURSOR_SHIFT | direction)
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// Shifts screen by one cell to the left or right
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#define shiftScreen(screen, direction) sendCommand(screen, SHIFT | DISPLAY_SHIFT | direction)
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// Sets the cursor position
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#define setCursor(screen, x, y) sendCommand(screen, DDRAM_AD_SET | (y << 6) | x)
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#endif // RASPBERRY_LCD_H
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