Initial commit

CMakeLists.txt

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+cmake_minimum_required(VERSION 3.13)
+
+add_library(picoled
+  include/picoled.h
+  include/picoled/SSD1306.h
+
+  src/picoled.cpp
+  src/SSD1306.cpp
+)
+
+target_link_libraries(picoled PUBLIC hardware_i2c pico_stdlib)
+target_include_directories(picoled PUBLIC include)

include/picoled.h

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+#ifndef PICOLED_H
+#define PICOLED_H
+
+#include <cstddef>
+
+namespace picoled
+{
+
+class pixel
+{
+public:
+  pixel() :
+    pixel(false)
+  {}
+
+  pixel(bool on) :
+    on(on)
+  {}
+
+  bool is_on() const { return on; }
+  void invert() { on = !on; }
+
+private:
+  bool on;
+};
+
+class oled
+{
+public:
+  oled(size_t width, size_t height);
+  virtual ~oled();
+
+  oled(const oled&) = delete;
+  oled(oled&&) = delete;
+
+  oled& operator=(const oled&) = delete;
+  oled& operator=(oled&&) = delete;
+
+  pixel& operator()(int x, int y);
+  const pixel& operator()(int x, int y) const;
+
+  void clear();
+
+  size_t get_width() const { return width; }
+  size_t get_height() const { return height; }
+
+  virtual void update() const = 0;
+
+protected:
+  size_t width;
+  size_t height;
+
+private:
+  pixel* pixels;
+};
+
+}
+
+#endif//PICOLED_H

include/picoled/SSD1306.h

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+#ifndef PICOLED_SSD1306_H
+#define PICOLED_SSD1306_H
+
+#include <cstdint>
+
+#include <hardware/i2c.h>
+
+#include "picoled.h"
+
+namespace picoled
+{
+
+class ssd1306 : public oled
+{
+public:
+  ssd1306(i2c_inst* i2c, uint8_t address);
+  virtual ~ssd1306();
+
+  void update() const override;
+
+private:
+  void command(uint8_t cmd) const;
+
+  i2c_inst* i2c;
+  uint8_t address;
+  uint8_t* buffer;
+};
+
+}
+
+#endif//PICOLED_SSD1306_H

src/SSD1306.cpp

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+#include "picoled/SSD1306.h"
+
+#include <cstring>
+
+// https://cdn-shop.adafruit.com/datasheets/SSD1306.pdf
+namespace
+{
+
+constexpr uint8_t MEMORY_MODE    = 0x20;
+constexpr uint8_t COLUMN_ADDRESS = 0x21;
+constexpr uint8_t PAGE_ADDRESS   = 0x22;
+constexpr uint8_t CONTRAST       = 0x81;
+constexpr uint8_t CHARGE_PUMP    = 0x8D;
+constexpr uint8_t SEGMENT_REMAP  = 0xA0;
+constexpr uint8_t ALLON_RESUME   = 0xA4;
+constexpr uint8_t ALLON          = 0xA5;
+constexpr uint8_t NORMAL_DISPLAY = 0xA6;
+constexpr uint8_t INVERT_DISPLAY = 0xA7;
+constexpr uint8_t MULTIPLEX      = 0xA8;
+constexpr uint8_t OFF            = 0xAE;
+constexpr uint8_t ON             = 0xAF;
+constexpr uint8_t COMSCAN_INC    = 0xC0;
+constexpr uint8_t COMSCAN_DEC    = 0xC8;
+constexpr uint8_t OFFSET         = 0xD3;
+constexpr uint8_t CLKDIV         = 0xD5;
+constexpr uint8_t PRECHARGE      = 0xD9;
+constexpr uint8_t COMPINS        = 0xDA;
+constexpr uint8_t VCOM_DETECT    = 0xDB;
+constexpr uint8_t LOW_COLUMN     = 0x00;
+constexpr uint8_t HIGH_COLUMN    = 0x10;
+constexpr uint8_t STARTLINE      = 0x40;
+constexpr uint8_t RIGHT_HSCROLL  = 0x26;
+constexpr uint8_t LEFT_HSCROLL   = 0x27;
+constexpr uint8_t VRIGHT_HSCROLL = 0x29;
+constexpr uint8_t VLEFT_HSCROLL  = 0x2A;
+constexpr uint8_t SCROLL_OFF     = 0x2E;
+constexpr uint8_t SCROLL_ON      = 0x2F;
+constexpr uint8_t VSCROLL_AREA   = 0xA3;
+
+}
+
+namespace picoled
+{
+
+ssd1306::ssd1306(i2c_inst* i2c, uint8_t address) :
+  oled(128, 64),
+  i2c(i2c),
+  address(address),
+  buffer(new uint8_t[128 * 64 / 8 + 1])
+{
+  // the user is expected to set GPIO func and pullup
+  // as well as initialize the i2c instance
+
+  command(OFF);
+  command(CLKDIV); command(0x80);
+  command(MULTIPLEX); command(63);
+  command(OFFSET); command(0);
+  command(STARTLINE | 0);
+  command(MEMORY_MODE); command(0);
+  command(SEGMENT_REMAP | 0);
+  command(COMSCAN_DEC);
+  command(COMPINS); command(0x12);
+  command(CONTRAST); command(0xCF);
+  command(PRECHARGE); command(0x22);
+  command(VCOM_DETECT); command(0x40);
+  command(NORMAL_DISPLAY);
+  command(SCROLL_OFF);
+  command(CHARGE_PUMP); command(0x14);
+  command(ALLON_RESUME);
+  command(ON);
+
+  buffer[0] = 0x40;
+}
+
+ssd1306::~ssd1306()
+{
+  delete[] buffer;
+}
+
+void ssd1306::update() const
+{
+  // clear display to zero
+  memset(&buffer[1], 0, width * height * sizeof(*buffer));
+
+  for (int x = 0; x < width; x++)
+  {
+    for (int y = 0; y < height; y++)
+    {
+      if (!(*this)(x, y).is_on()) { continue; }
+
+      const int index = (width - x - 1) + (y / 8) * width;
+      const uint8_t bits = 1 << (y & 7);
+
+      // add one to leave room for 0x40 data indicator at beginning of array
+      buffer[index + 1] |= bits;
+    }
+  }
+
+  command(PAGE_ADDRESS); command(0); command(7);
+  command(COLUMN_ADDRESS); command(0); command(width - 1);
+  i2c_write_blocking(i2c, address, buffer, width * height / 8 + 1, false);
+}
+
+void ssd1306::command(uint8_t cmd) const
+{
+  const uint8_t values[2] = { 0x00, cmd };
+  i2c_write_blocking(i2c, address, values, 2, false);
+}
+
+}

src/picoled.cpp

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+#include "picoled.h"
+
+namespace picoled
+{
+
+oled::oled(size_t width, size_t height) :
+  pixels(new pixel[width * height]),
+  width(width),
+  height(height)
+{}
+
+oled::~oled()
+{
+  delete[] pixels;
+}
+
+pixel& oled::operator()(int x, int y)
+{
+  return pixels[x + y * width];
+}
+
+const pixel& oled::operator()(int x, int y) const
+{
+  return pixels[x + y * width];
+}
+
+void oled::clear()
+{
+  for (int i = 0; i < width * height; i++)
+  {
+    pixels[i] = false;
+  }
+}
+
+}