Arduino for STM32

SSD1306 OLED problems

gigabyte091
Sat Mar 18, 2017 6:48 am
Hi,

Yesterday I installed STM32 for Arduino following this Youtube video:

[youtube]https://www.youtube.com/watch?v=1zVgLyuCejM[/youtube]

I’m running Arduino 1.8.1 IDE and I’m using OLED_I2C library found on this forum.

Problem is, i wrote a simple TEST code, and code compiles and upload to MCU via ST-Link v2 interface (MCU is STM32F103C8T6, standard ebay blue pill with 20k RAM and 128k ROM).

I tried every I2C output from MCU and nothing… blank screen. Tried example code, nothing, blank screen.
Tried on Arduino Uno to test OLED, and is working propertly.

Example of my test code:

#include <OLED_I2C.h>

OLED myOLED(SDA,SCL);

void setup() {
}

void loop() {

myOLED.begin();
myOLED.setBrightness(255);
myOLED.print("Hello World",CENTER,0);
myOLED.update();
delay(2000);

}

Pito
Sat Mar 18, 2017 10:37 am
Double check the SDA SCL pins are set properly. You need pull-ups on those pins too.
BennehBoy
Sat Mar 18, 2017 11:47 am
What OLED library is that, it looks to me like it’s bitbanging the i2C, can’t understand why it would need to know the pins otherwise.

If it is bitbanging then it’s probably an implementaion issue.

Perhaps try adafruit’s ssd1306 library.

gigabyte091
Sat Mar 18, 2017 12:09 pm
Nothing happens, i tried all three I2C and nothing…
gigabyte091
Sat Mar 18, 2017 12:17 pm
I found Adafruit STM32 I2C example, here is compiler output

C:\Program Files (x86)\Arduino\hardware\STM32\STM32F1\libraries\Adafruit_SSD1306\Adafruit_SSD1306_STM32.cpp: In member function 'virtual void Adafruit_SSD1306::drawPixel(int16_t, int16_t, uint16_t)':

C:\Program Files (x86)\Arduino\hardware\STM32\STM32F1\libraries\Adafruit_SSD1306\Adafruit_SSD1306_STM32.cpp:115:14: error: 'swap' was not declared in this scope

swap(x, y);

^

C:\Program Files (x86)\Arduino\hardware\STM32\STM32F1\libraries\Adafruit_SSD1306\Adafruit_SSD1306_STM32.cpp: In member function 'virtual void Adafruit_SSD1306::drawFastHLine(int16_t, int16_t, int16_t, uint16_t)':

C:\Program Files (x86)\Arduino\hardware\STM32\STM32F1\libraries\Adafruit_SSD1306\Adafruit_SSD1306_STM32.cpp:571:16: error: 'swap' was not declared in this scope

swap(x, y);

^

C:\Program Files (x86)\Arduino\hardware\STM32\STM32F1\libraries\Adafruit_SSD1306\Adafruit_SSD1306_STM32.cpp: In member function 'virtual void Adafruit_SSD1306::drawFastVLine(int16_t, int16_t, int16_t, uint16_t)':

C:\Program Files (x86)\Arduino\hardware\STM32\STM32F1\libraries\Adafruit_SSD1306\Adafruit_SSD1306_STM32.cpp:639:16: error: 'swap' was not declared in this scope

swap(x, y);

^

exit status 1
Error compiling for board Generic STM32F103C series.

BennehBoy
Sat Mar 18, 2017 12:40 pm
Use the stock adafruit library, not the STM32 variant in the core.
gigabyte091
Sat Mar 18, 2017 5:24 pm
Now its working but update speed is very slow… like every 500 ms, without any delay in code…
BennehBoy
Sat Mar 18, 2017 5:54 pm
Can you share your code.
gigabyte091
Sat Mar 18, 2017 6:38 pm
It is example code from Adafruit library, the only thing i changed is display address, from 0×3D to 0×3C

/*********************************************************************
This is an example for our Monochrome OLEDs based on SSD1306 drivers

Pick one up today in the adafruit shop!
------> http://www.adafruit.com/category/63_98

This example is for a 128x64 size display using I2C to communicate
3 pins are required to interface (2 I2C and one reset)

Adafruit invests time and resources providing this open source code,
please support Adafruit and open-source hardware by purchasing
products from Adafruit!

Written by Limor Fried/Ladyada for Adafruit Industries.
BSD license, check license.txt for more information
All text above, and the splash screen must be included in any redistribution
*********************************************************************/

#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define OLED_RESET 4
Adafruit_SSD1306 display(OLED_RESET);

#define NUMFLAKES 10
#define XPOS 0
#define YPOS 1
#define DELTAY 2

#define LOGO16_GLCD_HEIGHT 16
#define LOGO16_GLCD_WIDTH 16
static const unsigned char PROGMEM logo16_glcd_bmp[] =
{ B00000000, B11000000,
B00000001, B11000000,
B00000001, B11000000,
B00000011, B11100000,
B11110011, B11100000,
B11111110, B11111000,
B01111110, B11111111,
B00110011, B10011111,
B00011111, B11111100,
B00001101, B01110000,
B00011011, B10100000,
B00111111, B11100000,
B00111111, B11110000,
B01111100, B11110000,
B01110000, B01110000,
B00000000, B00110000 };

#if (SSD1306_LCDHEIGHT != 64)
#error("Height incorrect, please fix Adafruit_SSD1306.h!");
#endif

void setup() {
Serial.begin(9600);

// by default, we'll generate the high voltage from the 3.3v line internally! (neat!)
display.begin(SSD1306_SWITCHCAPVCC, 0x3C); // initialize with the I2C addr 0x3D (for the 128x64)
// init done

// Show image buffer on the display hardware.
// Since the buffer is intialized with an Adafruit splashscreen
// internally, this will display the splashscreen.
display.display();
delay(2000);

// Clear the buffer.
display.clearDisplay();

// draw a single pixel
display.drawPixel(10, 10, WHITE);
// Show the display buffer on the hardware.
// NOTE: You _must_ call display after making any drawing commands
// to make them visible on the display hardware!
display.display();
delay(2000);
display.clearDisplay();

// draw many lines
testdrawline();
display.display();
delay(2000);
display.clearDisplay();

// draw rectangles
testdrawrect();
display.display();
delay(2000);
display.clearDisplay();

// draw multiple rectangles
testfillrect();
display.display();
delay(2000);
display.clearDisplay();

// draw mulitple circles
testdrawcircle();
display.display();
delay(2000);
display.clearDisplay();

// draw a white circle, 10 pixel radius
display.fillCircle(display.width()/2, display.height()/2, 10, WHITE);
display.display();
delay(2000);
display.clearDisplay();

testdrawroundrect();
delay(2000);
display.clearDisplay();

testfillroundrect();
delay(2000);
display.clearDisplay();

testdrawtriangle();
delay(2000);
display.clearDisplay();

testfilltriangle();
delay(2000);
display.clearDisplay();

// draw the first ~12 characters in the font
testdrawchar();
display.display();
delay(2000);
display.clearDisplay();

// draw scrolling text
testscrolltext();
delay(2000);
display.clearDisplay();

// text display tests
display.setTextSize(1);
display.setTextColor(WHITE);
display.setCursor(0,0);
display.println("Hello, world!");
display.setTextColor(BLACK, WHITE); // 'inverted' text
display.println(3.141592);
display.setTextSize(2);
display.setTextColor(WHITE);
display.print("0x"); display.println(0xDEADBEEF, HEX);
display.display();
delay(2000);
display.clearDisplay();

// miniature bitmap display
display.drawBitmap(30, 16, logo16_glcd_bmp, 16, 16, 1);
display.display();
delay(1);

// invert the display
display.invertDisplay(true);
delay(1000);
display.invertDisplay(false);
delay(1000);
display.clearDisplay();

// draw a bitmap icon and 'animate' movement
testdrawbitmap(logo16_glcd_bmp, LOGO16_GLCD_HEIGHT, LOGO16_GLCD_WIDTH);
}

void loop() {

}

void testdrawbitmap(const uint8_t *bitmap, uint8_t w, uint8_t h) {
uint8_t icons[NUMFLAKES][3];

// initialize
for (uint8_t f=0; f< NUMFLAKES; f++) {
icons[f][XPOS] = random(display.width());
icons[f][YPOS] = 0;
icons[f][DELTAY] = random(5) + 1;

Serial.print("x: ");
Serial.print(icons[f][XPOS], DEC);
Serial.print(" y: ");
Serial.print(icons[f][YPOS], DEC);
Serial.print(" dy: ");
Serial.println(icons[f][DELTAY], DEC);
}

while (1) {
// draw each icon
for (uint8_t f=0; f< NUMFLAKES; f++) {
display.drawBitmap(icons[f][XPOS], icons[f][YPOS], bitmap, w, h, WHITE);
}
display.display();
delay(200);

// then erase it + move it
for (uint8_t f=0; f< NUMFLAKES; f++) {
display.drawBitmap(icons[f][XPOS], icons[f][YPOS], bitmap, w, h, BLACK);
// move it
icons[f][YPOS] += icons[f][DELTAY];
// if its gone, reinit
if (icons[f][YPOS] > display.height()) {
icons[f][XPOS] = random(display.width());
icons[f][YPOS] = 0;
icons[f][DELTAY] = random(5) + 1;
}
}
}
}

void testdrawchar(void) {
display.setTextSize(1);
display.setTextColor(WHITE);
display.setCursor(0,0);

for (uint8_t i=0; i < 168; i++) {
if (i == '\n') continue;
display.write(i);
if ((i > 0) && (i % 21 == 0))
display.println();
}
display.display();
delay(1);
}

void testdrawcircle(void) {
for (int16_t i=0; i<display.height(); i+=2) {
display.drawCircle(display.width()/2, display.height()/2, i, WHITE);
display.display();
delay(1);
}
}

void testfillrect(void) {
uint8_t color = 1;
for (int16_t i=0; i<display.height()/2; i+=3) {
// alternate colors
display.fillRect(i, i, display.width()-i*2, display.height()-i*2, color%2);
display.display();
delay(1);
color++;
}
}

void testdrawtriangle(void) {
for (int16_t i=0; i<min(display.width(),display.height())/2; i+=5) {
display.drawTriangle(display.width()/2, display.height()/2-i,
display.width()/2-i, display.height()/2+i,
display.width()/2+i, display.height()/2+i, WHITE);
display.display();
delay(1);
}
}

void testfilltriangle(void) {
uint8_t color = WHITE;
for (int16_t i=min(display.width(),display.height())/2; i>0; i-=5) {
display.fillTriangle(display.width()/2, display.height()/2-i,
display.width()/2-i, display.height()/2+i,
display.width()/2+i, display.height()/2+i, WHITE);
if (color == WHITE) color = BLACK;
else color = WHITE;
display.display();
delay(1);
}
}

void testdrawroundrect(void) {
for (int16_t i=0; i<display.height()/2-2; i+=2) {
display.drawRoundRect(i, i, display.width()-2*i, display.height()-2*i, display.height()/4, WHITE);
display.display();
delay(1);
}
}

void testfillroundrect(void) {
uint8_t color = WHITE;
for (int16_t i=0; i<display.height()/2-2; i+=2) {
display.fillRoundRect(i, i, display.width()-2*i, display.height()-2*i, display.height()/4, color);
if (color == WHITE) color = BLACK;
else color = WHITE;
display.display();
delay(1);
}
}

void testdrawrect(void) {
for (int16_t i=0; i<display.height()/2; i+=2) {
display.drawRect(i, i, display.width()-2*i, display.height()-2*i, WHITE);
display.display();
delay(1);
}
}

void testdrawline() {
for (int16_t i=0; i<display.width(); i+=4) {
display.drawLine(0, 0, i, display.height()-1, WHITE);
display.display();
delay(1);
}
for (int16_t i=0; i<display.height(); i+=4) {
display.drawLine(0, 0, display.width()-1, i, WHITE);
display.display();
delay(1);
}
delay(250);

display.clearDisplay();
for (int16_t i=0; i<display.width(); i+=4) {
display.drawLine(0, display.height()-1, i, 0, WHITE);
display.display();
delay(1);
}
for (int16_t i=display.height()-1; i>=0; i-=4) {
display.drawLine(0, display.height()-1, display.width()-1, i, WHITE);
display.display();
delay(1);
}
delay(250);

display.clearDisplay();
for (int16_t i=display.width()-1; i>=0; i-=4) {
display.drawLine(display.width()-1, display.height()-1, i, 0, WHITE);
display.display();
delay(1);
}
for (int16_t i=display.height()-1; i>=0; i-=4) {
display.drawLine(display.width()-1, display.height()-1, 0, i, WHITE);
display.display();
delay(1);
}
delay(250);

display.clearDisplay();
for (int16_t i=0; i<display.height(); i+=4) {
display.drawLine(display.width()-1, 0, 0, i, WHITE);
display.display();
delay(1);
}
for (int16_t i=0; i<display.width(); i+=4) {
display.drawLine(display.width()-1, 0, i, display.height()-1, WHITE);
display.display();
delay(1);
}
delay(250);
}

void testscrolltext(void) {
display.setTextSize(2);
display.setTextColor(WHITE);
display.setCursor(10,0);
display.clearDisplay();
display.println("scroll");
display.display();
delay(1);

display.startscrollright(0x00, 0x0F);
delay(2000);
display.stopscroll();
delay(1000);
display.startscrollleft(0x00, 0x0F);
delay(2000);
display.stopscroll();
delay(1000);
display.startscrolldiagright(0x00, 0x07);
delay(2000);
display.startscrolldiagleft(0x00, 0x07);
delay(2000);
display.stopscroll();
}

BennehBoy
Sat Mar 18, 2017 6:58 pm
Not to point out the obvious, but you realise there are a LOT of 2000 ms delays in this code?

The other thing to keep in mind is that the library is running i2c at 400khz. Every time the lib calls .display it writes a 1KB framebuffer out over that 400khz i2c bus…

SPI will happily operate at 18MHZ… so is just a bit faster.

You’d have to hook up a logic analyser to the i2C and see how saturated the bus is to work out what’s going on.

gigabyte091
Sun Mar 19, 2017 5:16 am
I know that there is 2 s delays, i tried same code on uno and its run much faster. Also i tried my simple code, just displaying ADC value, no delays in code, and screen is updated every 300 to 400 ms.

I dont have logic analyzer, just 2 channel dso

MAnand59
Sun Jun 25, 2017 1:57 pm
Hey can u tell me that on which pin did you connect the sda and scl of the oled to stm32.
i tried using the adafruit library example code with my stm32 but nothing displayed….
Pito
Sun Jun 25, 2017 2:10 pm
http://wiki.stm32duino.com/index.php?title=Blue_Pill

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