ssd1306.c File Reference

#include "ssd1306.h"

Go to the source code of this file.

Data Structures
struct	SSD1306_t

Macros
#define	ABS(x)   ((x) > 0 ? (x) : -(x))

Functions
void	SSD1306_WriteCommand (uint8_t command)
	Writes single byte command to slave.
void	SSD1306_WriteData (uint8_t dat)
	Writes single byte data to slave.
void	SSD1306_Init (void)
void	SSD1306_UpdateScreen (void)
	Updates buffer from internal RAM to LCD.
void	SSD1306_ToggleInvert (void)
	Toggles pixels invertion inside internal RAM.
void	SSD1306_Fill (uint8_t color)
	Fills entire LCD with desired color.
void	SSD1306_DrawPixel (uint16_t x, uint16_t y, uint8_t color)
	Draws pixel at desired location.
void	SSD1306_GotoXY (uint16_t x, uint16_t y)
	Sets cursor pointer to desired location for strings.
void	SSD1306_DrawLine (uint16_t x0, uint16_t y0, uint16_t x1, uint16_t y1, uint8_t c)
	Draws line on LCD.
void	SSD1306_ON (void)
void	SSD1306_OFF (void)

Variables
static __XDATA uint8_t	SSD1306_Buffer_all [SSD1306_WIDTH *SSD1306_HEIGHT/8]
static SSD1306_t	SSD1306

Macro Definition Documentation

ABS

#define ABS

(

x

)

((x) > 0 ? (x) : -(x))

Definition at line 18 of file ssd1306.c.

Function Documentation

SSD1306_DrawLine()

void SSD1306_DrawLine	(	uint16_t	x0,
		uint16_t	y0,
		uint16_t	x1,
		uint16_t	y1,
		uint8_t	c
	)

Draws line on LCD.

Note

SSD1306_UpdateScreen() must be called after that in order to see updated LCD screen

Parameters

x0	Line X start point. Valid input is 0 to SSD1306_WIDTH - 1
y0	Line Y start point. Valid input is 0 to SSD1306_HEIGHT - 1
x1	Line X end point. Valid input is 0 to SSD1306_WIDTH - 1
y1	Line Y end point. Valid input is 0 to SSD1306_HEIGHT - 1
c	Color to be used. This parameter can be a value of SSD1306_COLOR_t enumeration

Return values

None

Definition at line 223 of file ssd1306.c.

{
    int16_t dx, dy, sx, sy, err, e2, i, tmp; 
    
    /* Check for overflow */
    if (x0 >= SSD1306_WIDTH)
    {
        x0 = SSD1306_WIDTH - 1;
    }
    if (x1 >= SSD1306_WIDTH)
    {
        x1 = SSD1306_WIDTH - 1;
    }
    if (y0 >= SSD1306_HEIGHT)
    {
        y0 = SSD1306_HEIGHT - 1;
    }
    if (y1 >= SSD1306_HEIGHT)
    {
        y1 = SSD1306_HEIGHT - 1;
    }
    
    dx = (x0 < x1) ? (x1 - x0) : (x0 - x1); 
    dy = (y0 < y1) ? (y1 - y0) : (y0 - y1); 
    sx = (x0 < x1) ? 1 : -1; 
    sy = (y0 < y1) ? 1 : -1; 
    err = ((dx > dy) ? dx : -dy) / 2; 
 
    if (dx == 0)
    {
        if (y1 < y0)
        {
            tmp = y1;
            y1 = y0;
            y0 = tmp;
        }
        
        if (x1 < x0)
        {
            tmp = x1;
            x1 = x0;
            x0 = tmp;
        }
        
        /* Vertical line */
        for (i = y0; i <= y1; i++)
        {
            SSD1306_DrawPixel(x0, i, c);
        }
        
        /* Return from function */
        return;
    }
    
    if (dy == 0)
    {
        if (y1 < y0)
        {
            tmp = y1;
            y1 = y0;
            y0 = tmp;
        }
        
        if (x1 < x0)
        {
            tmp = x1;
            x1 = x0;
            x0 = tmp;
        }
        
        /* Horizontal line */
        for (i = x0; i <= x1; i++)
        {
            SSD1306_DrawPixel(i, y0, c);
        }
        
        /* Return from function */
        return;
    }
 
    while (1)
    {
        SSD1306_DrawPixel(x0, y0, c);
        if (x0 == x1 && y0 == y1)
        {
            break;
        }
        e2 = err;
        if (e2 > -dx)
        {
            err -= dy;
            x0 += sx;
        }
        if (e2 < dy)
        {
            err += dx;
            y0 += sy;
        }
    }
}

SSD1306_DrawPixel()

void SSD1306_DrawPixel	(	uint16_t	x,
		uint16_t	y,
		uint8_t	color
	)

Draws pixel at desired location.

Note

SSD1306_UpdateScreen() must called after that in order to see updated LCD screen

Parameters

x	X location. This parameter can be a value between 0 and SSD1306_WIDTH - 1
y	Y location. This parameter can be a value between 0 and SSD1306_HEIGHT - 1
color	Color to be used for screen fill. This parameter can be a value of SSD1306_COLOR_t enumeration

Return values

None

Definition at line 191 of file ssd1306.c.

{
    if (x >= SSD1306_WIDTH || y >= SSD1306_HEIGHT)
    {
        /* Error */
        return;
    }
 
    /* Check if pixels are inverted */
    if (SSD1306.Inverted)
    {
        color = (uint8_t)!color;
    }
 
    /* Set color */
    if (color == SSD1306_COLOR_WHITE)
    {
        SSD1306_Buffer_all[x + (y / 8) * SSD1306_WIDTH] |= 1 << (y % 8);
    }
    else
    {
        SSD1306_Buffer_all[x + (y / 8) * SSD1306_WIDTH] &= ~(1 << (y % 8));
    }
}

SSD1306_Fill()

void SSD1306_Fill

(

uint8_t

Color

)

Fills entire LCD with desired color.

Note

SSD1306_UpdateScreen() must be called after that in order to see updated LCD screen

Parameters

Color

Color to be used for screen fill. This parameter can be a value of SSD1306_COLOR_t enumeration

Definition at line 181 of file ssd1306.c.

{
    if (SSD1306.Inverted)
    {
        color = (uint8_t)!color;
    }
    /* Set memory */
    memset(SSD1306_Buffer_all, (color == SSD1306_COLOR_BLACK) ? 0x00 : 0xFF, SSD1306_WIDTH * SSD1306_HEIGHT / 8);
}

SSD1306_GotoXY()

void SSD1306_GotoXY	(	uint16_t	x,
		uint16_t	y
	)

Sets cursor pointer to desired location for strings.

Parameters

x	X location. This parameter can be a value between 0 and SSD1306_WIDTH - 1
y	Y location. This parameter can be a value between 0 and SSD1306_HEIGHT - 1

Return values

None

Definition at line 216 of file ssd1306.c.

{
    /* Set write pointers */
    SSD1306.CurrentX = x;
    SSD1306.CurrentY = y;
}

SSD1306_Init()

void SSD1306_Init

(

void

)

Initializes SSD1306 LCD

Set the lower start column address of pointer by command 00h~0Fh. Set the upper start column address of pointer by command 10h~1Fh.

set contrast control register, 2 bytes, 0x00 - 0xFF

0xA4,Output follows RAM content 0xA5,Output ignores RAM content

0xA6, Normal display (RESET) 0xA7, Inverse display

Set the page start address of the target display location by command B0h to B7h For Page Addressing Mode only

Set Page Address, 3 bytes For Horizontal and Vertical Addressing Mode only

COM Output Scan Direction 0xC0: normal mode (RESET) Scan from COM0 to COM[N –1] 0xC8: remapped mode. Scan from COM[N-1] to COM0

Set display RAM display start line register from 0-63

Segment Re-map 0xA0: column address 0 is mapped to SEG0 (RESET), 0xA1: column address 127 is mapped to SEG0

Set MUX ratio to N+1 MUX N=A[5:0]: from 16MUX to 64MUX, RESET=111111b (i.e. 63d, 64MUX) A[5:0] from 0 to 14 are invalid entry.

Set Display Offset, Set vertical shift by COM from 0d~63d The value is reset to 00h after RESET

Set COM Pins Hardware Configuration A[4]=0b, Sequential COM pin configuration A[4]=1b(RESET), Alternative COM pin configuration A[5]=0b(RESET), Disable COM Left/Right remap A[5]=1b, Enable COM Left/Right remap

Set Display Divide Ratio/Oscillator Frequency

Set Pre-charge Period

Set V COMH Deselect Level 0x00: 0.65 * Vcc 0x10: 0.77 * Vcc (RESET) 0x11: 0.83 * Vcc

charge pump setting 0x10: Disable charge pump(RESET) 0x14: Enable charge pump during display on

0xAE, Display OFF (sleep mode), 0xAF, Display ON in normal mode

Definition at line 44 of file ssd1306.c.

{
    SYS_Delay(100);
 
    /* Init LCD */
    SSD1306_WriteCommand(0xAE); //display off
    SSD1306_WriteCommand(0x00); //---set low column address
    SSD1306_WriteCommand(0x10); //---set high column address
 
    SSD1306_WriteCommand(0x81);
    SSD1306_WriteCommand(0x7F);
    SSD1306_WriteCommand(0xA4);
    SSD1306_WriteCommand(0xA6);
    /* 0x20,Set Memory Addressing Mode, 2 bytes, 
     *   0x00,Horizontal Addressing Mode (slide horizontally and goto next page)
     *   0x01,Vertical Addressing Mode (slide vertically and goto next column)
     *   0x02,Page Addressing Mode (RESET) (slide horizontally and remain in the same page)
     *   0x03,Invalid
    */
    SSD1306_WriteCommand(0x20); 
    SSD1306_WriteCommand(0x00);
    SSD1306_WriteCommand(0xB0);
    SSD1306_WriteCommand(0x22);
    SSD1306_WriteCommand(0x00); // From Page 0
    SSD1306_WriteCommand(0x07); // To Page 7
 
    SSD1306_WriteCommand(0xC8); //Set COM Output Scan Direction
    SSD1306_WriteCommand(0x40);
    SSD1306_WriteCommand(0xA1);
    SSD1306_WriteCommand(0xA8);
    SSD1306_WriteCommand(0x3F);
    SSD1306_WriteCommand(0xD3);
    SSD1306_WriteCommand(0x00); // offset in vertical
    SSD1306_WriteCommand(0xDA);
    SSD1306_WriteCommand(0x12); // A[4]=0, A[5]=1
    SSD1306_WriteCommand(0xD5);
    SSD1306_WriteCommand(0xF0); // divide ratio
    SSD1306_WriteCommand(0xD9);
    SSD1306_WriteCommand(0x22);
    SSD1306_WriteCommand(0xDB);
    SSD1306_WriteCommand(0x10);
 
    SSD1306_WriteCommand(0x8D);
    SSD1306_WriteCommand(0x14);
 
    SSD1306_WriteCommand(0xAF);
 
    /* Clear screen */
    SSD1306_Fill(SSD1306_COLOR_BLACK);
 
    /* Update screen */
    SSD1306_UpdateScreen();
 
    /* Set default values */
    SSD1306.CurrentX = 0;
    SSD1306.CurrentY = 0;
 
    /* Initialized OK */
    SSD1306.Initialized = 1;
}

SSD1306_OFF()

void SSD1306_OFF

(

void

)

Definition at line 330 of file ssd1306.c.

{
    SSD1306_WriteCommand(0x8D);
    SSD1306_WriteCommand(0x10);
    SSD1306_WriteCommand(0xAE);
}

SSD1306_ON()

void SSD1306_ON

(

void

)

Definition at line 324 of file ssd1306.c.

{
    SSD1306_WriteCommand(0x8D);
    SSD1306_WriteCommand(0x14);
    SSD1306_WriteCommand(0xAF);
}

SSD1306_ToggleInvert()

void SSD1306_ToggleInvert

(

void

)

Toggles pixels invertion inside internal RAM.

Note

SSD1306_UpdateScreen() must be called after that in order to see updated LCD screen

Definition at line 167 of file ssd1306.c.

{
    uint16_t i;
    
    /* Toggle invert */
    SSD1306.Inverted = !SSD1306.Inverted;
    
    /* Do memory toggle */
    for (i = 0; i < sizeof(SSD1306_Buffer_all); i++)
    {
        SSD1306_Buffer_all[i] = ~SSD1306_Buffer_all[i];
    }
}

SSD1306_UpdateScreen()

void SSD1306_UpdateScreen

(

void

)

Updates buffer from internal RAM to LCD.

Note

This function must be called each time you do some changes to LCD, to update buffer from RAM to LCD

Definition at line 162 of file ssd1306.c.

{
    I2C_Write(SSD1306_I2C_ADDR, 0x40, SSD1306_Buffer_all, SSD1306_WIDTH * SSD1306_HEIGHT / 8);
}

SSD1306_WriteCommand()

void SSD1306_WriteCommand

(

uint8_t

command

)

Writes single byte command to slave.

Parameters

command

command to be written

Definition at line 34 of file ssd1306.c.

{
    I2C_Write(SSD1306_I2C_ADDR, 0x00, &command, 1);
}

SSD1306_WriteData()

void SSD1306_WriteData

(

uint8_t

dat

)

Writes single byte data to slave.

Parameters

dat	data to be written

Definition at line 39 of file ssd1306.c.

{
    I2C_Write(SSD1306_I2C_ADDR, 0x40, &dat, 1);
}

Variable Documentation

SSD1306

SSD1306_t SSD1306

static

Definition at line 32 of file ssd1306.c.

SSD1306_Buffer_all

__XDATA uint8_t SSD1306_Buffer_all[SSD1306_WIDTH *SSD1306_HEIGHT/8]

static

Definition at line 21 of file ssd1306.c.