Hi,
I'm trying to write my own ssd1306 library using stm32 maple mini board.
So the stm32_ssd1306 library is using some functions of Arduino Adafuit_GFX master library using C++ public inheritance.
And I want to run my library without Adafuit_GFX master library support.
But as I'm copying the functions to my library, I noticed the protected "rotation" variable is used to determine the rotation of the display and used in different other functions. But what I don't understand and couldn't find is where this variable is modified ?
Edit:
I want to add that the reason that I'm searching for this variable is that I want to know how it's manipulated and try to copy the function that modify/manipulate this variable.
OK, got one part of the problem:
void Adafruit_GFX::setRotation(uint8_t x) {
rotation = (x & 3);
This is how, but now I should check where setRotation() is used.
God gave you grep.
The Arduino IDE editor gave you ctrl-F
I couldn't find setRotation()
anywhere, whether in example code or in the libraries.
lines 1310-1330
/**************************************************************************/
/*!
@brief Set rotation setting for display
@param x 0 thru 3 corresponding to 4 cardinal rotations
*/
/**************************************************************************/
void Adafruit_GFX::setRotation(uint8_t x) {
rotation = (x & 3);
switch (rotation) {
case 0:
case 2:
_width = WIDTH;
_height = HEIGHT;
break;
case 1:
case 3:
_width = HEIGHT;
_height = WIDTH;
break;
}
}
A hardware class that inherits from Adafruit_GFX will implement the hardware specific rotation code and update its parent Adafruit_GFX::setRotation()
The real mystery is: Why do you want to avoid Adafruit_GFX?
David.
david_prentice:
lines 1310-1330
A hardware class that inherits from Adafruit_GFX will implement the hardware specific rotation code and update its parent Adafruit_GFX::setRotation()
Yeah that's the function definition.
I want to know where it's used in the code whether in example of library code ?
The real mystery is: Why do you want to avoid Adafruit_GFX?
I want to teach myself how to write this library in C, then I do my own version of C++.
That way I learn how to run something and also learn something about how a complete library with the necessary functions is written. Otherwise no one would teach me, I better teach myself and a get a fortune in my country.
Programming would be something shiny especially in embedded systems, I've done simple courses in PIC micrcontrollers, I learned about my abilities and what I need for the next level.
I wanna be a professional trainer and buy myself a BMW M5 sport 
Yeah I'm so happy I was able to copy the stm32 ssd1306 library written in C++ and convert it to a C version without Adafruit support and it worked
#include <avr/pgmspace.h>
#include <stdlib.h>
#include <Wire.h>
#include "ssd1306_stm32.h"
#ifndef swap
#define swap(a, b) { int16_t t = a; a = b; b = t; }
#endif
uint8_t rotation, width = 128, height = 64, _i2caddr, _vccstate;
static uint8_t buffer[1024] = {0};
void ssd1306_start(uint8_t vccstate, uint8_t i2caddr) {
_vccstate = vccstate;
_i2caddr = i2caddr;
// I2C Init
Wire.begin();
/*if (reset) {
// Setup reset pin direction (used by both SPI and I2C)
pinMode(rst, OUTPUT); digitalWrite(rst, HIGH);
delay(1); // VDD rise at start, wait 1ms
digitalWrite(rst, LOW); // bring reset low
delay(10); // wait 10ms
digitalWrite(rst, HIGH); // bring out of reset
}*/
// Init sequence for 128x64 OLED module
ssd1306_cmd(SSD1306_DISPLAYOFF); // 0xAE
ssd1306_cmd(SSD1306_SETDISPLAYCLOCKDIV); // 0xD5
ssd1306_cmd(0x80); // the suggested ratio 0x80
ssd1306_cmd(SSD1306_SETMULTIPLEX); // 0xA8
ssd1306_cmd(0x3F);
ssd1306_cmd(SSD1306_SETDISPLAYOFFSET); // 0xD3
ssd1306_cmd(0x0); // no offset
ssd1306_cmd(SSD1306_SETSTARTLINE | 0x0); // line #0
ssd1306_cmd(SSD1306_CHARGEPUMP); // 0x8D
if (vccstate == SSD1306_EXTERNALVCC)
{ ssd1306_cmd(0x10); }
else
{ ssd1306_cmd(0x14); }
ssd1306_cmd(SSD1306_MEMORYMODE); // 0x20
ssd1306_cmd(0x00); // 0x0 act like ks0108
ssd1306_cmd(SSD1306_SEGREMAP | 0x1);
ssd1306_cmd(SSD1306_COMSCANDEC);
ssd1306_cmd(SSD1306_SETCOMPINS); // 0xDA
ssd1306_cmd(0x12);
ssd1306_cmd(SSD1306_SETCONTRAST); // 0x81
if (vccstate == SSD1306_EXTERNALVCC)
{ ssd1306_cmd(0x9F); }
else
{ ssd1306_cmd(0xCF); }
ssd1306_cmd(SSD1306_SETPRECHARGE); // 0xd9
if (vccstate == SSD1306_EXTERNALVCC)
{ ssd1306_cmd(0x22); }
else
{ ssd1306_cmd(0xF1); }
ssd1306_cmd(SSD1306_SETVCOMDETECT); // 0xDB
ssd1306_cmd(0x40);
ssd1306_cmd(SSD1306_DISPLAYALLON_RESUME); // 0xA4
ssd1306_cmd(SSD1306_NORMALDISPLAY); // 0xA6
ssd1306_cmd(SSD1306_DISPLAYON);//--turn on oled panel
}
void ssd1306_cmd(uint8_t c){
uint8_t control = 0x00; // Co = 0, D/C = 0
Wire.beginTransmission(_i2caddr);
WIRE_WRITE(control);
WIRE_WRITE(c);
Wire.endTransmission();
}
void ssd1306_data(uint8_t c){
uint8_t control = 0x40; // Co = 0, D/C = 1
Wire.beginTransmission(_i2caddr);
WIRE_WRITE(control);
WIRE_WRITE(c);
Wire.endTransmission();
}
void ssd1306_clearDisplay(void){
memset(buffer, 0, 1024);
}
void ssd1306_invertDisplay(uint8_t i){
if (i) {
ssd1306_cmd(SSD1306_INVERTDISPLAY);
} else {
ssd1306_cmd(SSD1306_NORMALDISPLAY);
}
}
void ssd1306_display(void){
ssd1306_cmd(SSD1306_COLUMNADDR);
ssd1306_cmd(0); // Column start address (0 = reset)
ssd1306_cmd(SSD1306_WIDTH-1); // Column end address (127 = reset)
ssd1306_cmd(SSD1306_PAGEADDR);
ssd1306_cmd(0); // Page start address (0 = reset)
ssd1306_cmd(7); // Page end address
// I2C
for (uint16_t i=0; i<1024; i++) {
// send a bunch of data in one xmission
Wire.beginTransmission(_i2caddr);
WIRE_WRITE(0x40);
for (uint8_t x=0; x<16; x++) {
WIRE_WRITE(buffer[i]);
i++;
}
i--;
Wire.endTransmission();
}
}
// lcd control functions
void ssd1306_scrl_right(uint8_t start, uint8_t stop){
ssd1306_cmd(SSD1306_RIGHT_HORIZONTAL_SCROLL);
ssd1306_cmd(0X00);
ssd1306_cmd(start);
ssd1306_cmd(0X0F);
ssd1306_cmd(stop);
ssd1306_cmd(0X00);
ssd1306_cmd(0XFF);
ssd1306_cmd(SSD1306_ACTIVATE_SCROLL);
}
void ssd1306_scrl_left(uint8_t start, uint8_t stop){
ssd1306_cmd(SSD1306_LEFT_HORIZONTAL_SCROLL);
ssd1306_cmd(0X00);
ssd1306_cmd(start);
ssd1306_cmd(7);
ssd1306_cmd(stop);
ssd1306_cmd(0X00);
ssd1306_cmd(0XFF);
ssd1306_cmd(SSD1306_ACTIVATE_SCROLL);
}
void ssd1306_scrl_d_right(uint8_t start, uint8_t stop){
ssd1306_cmd(SSD1306_SET_VERTICAL_SCROLL_AREA);
ssd1306_cmd(0X00);
ssd1306_cmd(SSD1306_HEIGHT);
ssd1306_cmd(SSD1306_VERTICAL_AND_RIGHT_HORIZONTAL_SCROLL);
ssd1306_cmd(0X00);
ssd1306_cmd(start);
ssd1306_cmd(0X00);
ssd1306_cmd(stop);
ssd1306_cmd(0X01);
ssd1306_cmd(SSD1306_ACTIVATE_SCROLL);
}
void ssd1306_scrl_d_left(uint8_t start, uint8_t stop){
ssd1306_cmd(SSD1306_SET_VERTICAL_SCROLL_AREA);
ssd1306_cmd(0X00);
ssd1306_cmd(SSD1306_HEIGHT);
ssd1306_cmd(SSD1306_VERTICAL_AND_LEFT_HORIZONTAL_SCROLL);
ssd1306_cmd(0X00);
ssd1306_cmd(start);
ssd1306_cmd(0X00);
ssd1306_cmd(stop);
ssd1306_cmd(0X01);
ssd1306_cmd(SSD1306_ACTIVATE_SCROLL);
}
void ssd1306_stop_scrl(void){
ssd1306_cmd(SSD1306_DEACTIVATE_SCROLL);
}
void ssd1306_dim(boolean dim){
uint8_t contrast;
if (dim) {
contrast = 0; // Dimmed display
} else {
if (_vccstate == SSD1306_EXTERNALVCC) {
contrast = 0x9F;
} else {
contrast = 0xCF;
}
}
// the range of contrast to too small to be really useful
// it is useful to dim the display
ssd1306_cmd(SSD1306_SETCONTRAST);
ssd1306_cmd(contrast);
}
void ssd1306_set_rotation(uint8_t x) {
rotation = (x & 3);
switch(rotation) {
case 0:
case 2:
width = SSD1306_WIDTH;
height = SSD1306_HEIGHT;
break;
case 1:
case 3:
width = SSD1306_HEIGHT;
height = SSD1306_WIDTH;
break;
}
}
void ssd1306_drawPixel(int16_t x, int16_t y, uint16_t color){
if ((x < 0) || (x >= width) || (y < 0) || (y >= height))
return;
// check rotation, move pixel around if necessary
switch (rotation) {
case 1:
swap(x, y);
x = width - x - 1;
break;
case 2:
x = width - x - 1;
y = height - y - 1;
break;
case 3:
swap(x, y);
y = height - y - 1;
break;
}
// x is which column
switch (color)
{
case WHITE: buffer[x+ (y/8)*SSD1306_WIDTH] |= (1 << (y&7)); break;
case BLACK: buffer[x+ (y/8)*SSD1306_WIDTH] &= ~(1 << (y&7)); break;
case INVERSE: buffer[x+ (y/8)*SSD1306_WIDTH] ^= (1 << (y&7)); break;
}
}
Now I can investigate the code parts more and then I would consider doing a C++ version of my own.
But I still need to know where
setRotation()
is used.
Because I want to know the parts of code that modify the rotation of the display.