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

#define SCREEN_WIDTH 128    // OLED display width, in pixels
#define SCREEN_HEIGHT 64    // OLED display height, in pixels
#define OLED_RESET     -1   // Reset pin # (or -1 if sharing Arduino reset pin)
#define SCREEN_ADDRESS 0x3c ///< See datasheet for Address; 0x3D for 128x64, 0x3C for 128x32
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

#define MAX_PIN 26

extern const int PIN_STM_32[] = { PA3, PA2, PA1, PA0, PB12, PB13, PB14, PB15, PA8, PA9, PA10, PA15, PB3, PB4, PB5, PB9, PC15, PC14, PB11, PB10, PB1, PB0, PA7, PA6, PA5, PA4 };

// Function to set a pin to high impedance (acts like open drain output)
void go_z(int pin)
{
  pinMode(pin, INPUT);
  digitalWrite(pin, HIGH);
}
//
// Function to set a pin as an input with a pullup
void go_pu(int pin)
{
  pinMode(pin, INPUT_PULLUP);
  digitalWrite(pin, HIGH);
}
//
// Function to send a pin to a logic low
void go_0(int pin)
{
  pinMode(pin, OUTPUT);
  digitalWrite(pin, LOW);
}
//
// Function to send a pin to a logic high
void go_1(int pin)
{
  pinMode(pin, OUTPUT);
  digitalWrite(pin, HIGH);
}
//

// **************** Setup *******************

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

  // SSD1306_SWITCHCAPVCC = generate display voltage from 3.3V internally
  if(!display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS)) {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;); // Don't proceed, loop forever
  }
  display.clearDisplay();
  for(int i=0; i<MAX_PIN; i++) {
    //go_z(PIN_STM_32[i];
    } 
  }

// **************** Loop *******************

void loop() {
  // put your main code here, to run repeatedly:
  display.setTextSize(1);             // Normal 1:1 pixel scale
  display.setTextColor(SSD1306_WHITE);        // Draw white text
  display.setCursor(0,0);             // Start at top-left corner
  display.println(F("Hello, world!"));

  display.setTextColor(SSD1306_BLACK, SSD1306_WHITE); // Draw 'inverse' text
  display.println(3.141592);

  display.setTextSize(2);             // Draw 2X-scale text
  display.setTextColor(SSD1306_WHITE);
  display.print(F("0x")); display.println(0xDEADBEEF, HEX);

  display.display();
  delay(2000);
}