add support for SH1106/SSD1306

Author: AlexIII

img/res-mod-sh1106.jpg

@@ -12,6 +12,9 @@ Just 3 components needed:
 
 [Youtube video](https://www.youtube.com/watch?v=635SnybBRD8)
 
+**Update**
+Now supporting [OLED display SH1106/SSD1306 I2C](#using-oled-display-sh1106/ssd1306-i2c).
+
 ## Instructions
 
 0. Assemble
@@ -22,6 +25,32 @@ Just 3 components needed:
 2. Play!
 3. Repeat from step 2
 
+## Using OLED display SH1106/SSD1306 I2C
+
+<img width="250" src="img/t-rex-demo-sh1106.gif" />
+
+0. In order to use SH1106/SSD1306 you will need to add two 470 ohm resistors to the dispaly board. 
+You can add these resistors right on top of 10k resistors that already present (or replace them).
+
+<img width="250" src="img/res-mod-sh1106.jpg" />
+
+1. Assemble
+
+<img width="600" src="img/sch-sh1106.png" />
+
+3. Select OLED display type at the beginning of `t-rex-duino.ino` sketch by uncommenting one of the following lines (SSD1309 selected by default).
+```
+//#define LCD_SSD1309
+//#define LCD_SH1106
+//#define LCD_SSD1306
+```
+Flash the sketch.
+
+Note that in order to achieve desirable performance I2C is substantially overclocked (it works at 800kHz vs 400kHz as per display specification).
+It is possible that not every display will work under these conditions.
+The display I have works fine mostly, but a stray broken frame still appears now and then.
+As much as I can assume **small artifacts are unavoidable with this display**.
+
 ## License
 
 MIT License © github.com/AlexIII

img/sch-sh1106.png

@@ -0,0 +1,126 @@
+/*
+ * Project name: T-rex-duino
+ * Description: T-rex game from Chrome brower rewritten for Arduino
+ * Project page: https://github.com/AlexIII/t-rex-duino
+ * Author: github.com/AlexIII
+ * E-mail: [email protected]
+ * License: MIT
+*/ 
+
+#ifndef _I2C_CALSS_H_
+#define _I2C_CALSS_H_
+
+#include <compat/twi.h>
+
+struct I2C {
+  I2C() {}
+  
+  static void init(const uint32_t clock) {
+    TWSR = 0;                         // no prescaler
+    TWBR = ((F_CPU/clock)-16)/2;  // must be > 10 for stable operation
+  }
+  
+  static void deinit(void) {
+    TWBR = 0;
+    TWCR = 0;
+  }
+
+  static uint8_t start(uint8_t address) {
+    uint8_t   twst, i;
+    // send START condition
+    TWCR = (1<<TWINT) | (1<<TWSTA) | (1<<TWEN);
+  
+    // wait until transmission completed
+    //while(!(TWCR & (1<<TWINT)));
+    for(i = 255; i; --i) {
+      if(TWCR & (1<<TWINT)) break;
+      asm volatile("nop");
+      asm volatile("nop");
+    }
+    if(!i) return 0xFF;
+  
+    // check value of TWI Status Register. Mask prescaler bits.
+    twst = TW_STATUS & 0xF8;
+    if ( (twst != TW_START) && (twst != TW_REP_START)) return 1;
+  
+    // send device address
+    TWDR = address;
+    TWCR = (1<<TWINT) | (1<<TWEN);
+  
+    // wail until transmission completed and ACK/NACK has been received
+    //while(!(TWCR & (1<<TWINT)));
+    for(i = 255; i; --i) {
+      if(TWCR & (1<<TWINT)) break;
+      asm volatile("nop");
+      asm volatile("nop");
+    }
+    if(!i) return 0xFF;
+    
+    // check value of TWI Status Register. Mask prescaler bits.
+    twst = TW_STATUS & 0xF8;
+    if ( (twst != TW_MT_SLA_ACK) && (twst != TW_MR_SLA_ACK) ) return 1;
+  
+    return 0;
+  }
+
+  static void stop(void) {
+    //send stop condition
+    TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWSTO);
+    
+    // wait until stop condition is executed and bus released
+    //while(TWCR & (1<<TWSTO));
+    for(uint8_t i = 255; i; --i) {
+      if(!(TWCR & (1<<TWSTO))) break;
+      asm volatile("nop");
+      asm volatile("nop");
+    }
+  }
+  
+  static uint8_t write(uint8_t data) {  
+    uint8_t   twst;
+      
+    // send data to the previously addressed device
+    TWDR = data;
+    TWCR = (1<<TWINT) | (1<<TWEN);
+  
+    // wait until transmission completed
+    //while(!(TWCR & (1<<TWINT)));
+    uint8_t i;
+    for(i = 255; i; --i) {
+      if(TWCR & (1<<TWINT)) break;
+      asm volatile("nop");
+      asm volatile("nop");
+    }
+    if(!i) return 0xFF;
+    
+    // check value of TWI Status Register. Mask prescaler bits
+    twst = TW_STATUS & 0xF8;
+    if( twst != TW_MT_DATA_ACK) return twst;
+    return 0;
+  }
+
+  static uint8_t readAck(void) {
+    TWCR = (1<<TWINT) | (1<<TWEN) | (1<<TWEA);
+    //while(!(TWCR & (1<<TWINT)));
+    for(uint8_t i = 255; i; --i) {
+      if(TWCR & (1<<TWINT)) break;
+      asm volatile("nop");
+      asm volatile("nop");
+    }
+    return TWDR;
+  }
+  
+  static uint8_t readNak(void) {
+    TWCR = (1<<TWINT) | (1<<TWEN);
+    //while(!(TWCR & (1<<TWINT)));
+    for(uint8_t i = 255; i; --i) {
+      if(TWCR & (1<<TWINT)) break;
+      asm volatile("nop");
+      asm volatile("nop");
+    }
+    return TWDR;
+  }
+};
+
+
+#endif

img/sch.png

@@ -0,0 +1,120 @@
+/*
+ * Project name: T-rex-duino
+ * Description: T-rex game from Chrome brower rewritten for Arduino
+ * Project page: https://github.com/AlexIII/t-rex-duino
+ * Author: github.com/AlexIII
+ * E-mail: [email protected]
+ * License: MIT
+*/ 
+
+#ifndef _SH1106_H_
+#define _SH1106_H_
+
+#define SH1106_I2C_SCL_CLOCK  800000UL
+#define SH1106_I2C_ADDR 0b01111000
+#define SH1106_COMMAND 0x00
+#define SH1106_DATA 0x40
+
+#define SH1106_COLS_USED 128
+#define SH1106_PAGES 8
+
+#ifndef LCD_SSD1306
+  #define SH1106_COLS_TOTAL 130
+#else 
+  #define SH1106_COLS_TOTAL SH1106_COLS_USED
+#endif
+
+template<class I2C_TYPE>
+class SH1106 {
+  I2C_TYPE &i2c;
+  const uint16_t screenBufferSize;
+public:
+  enum AddressingMode {
+    HorizontalAddressingMode = 0x00,
+    VerticalAddressingMode = 0x01,
+    PageAddressingMode = 0x02,
+  };
+  SH1106(I2C_TYPE &i2c, const uint16_t screenBufferSize): 
+    i2c(i2c), screenBufferSize(screenBufferSize) {}
+  void begin() {
+    uint8_t col = 0;
+    uint8_t page = 0;
+  }
+  void fillScreen(const uint8_t* buffer) {
+    reinit();
+    sendd(buffer, screenBufferSize);
+  }
+  void fillScreen(const uint8_t* buffer, const uint16_t size, const uint8_t stride = 0) { //stride is not supported
+    reinit();
+    sendd(buffer, size);
+  }
+  void setInverse(const bool v) {
+    inverted = v;
+    reinit();
+  }
+  //Only PageAddressingMode works for SH1106
+  //Here we're emulating HorizontalAddressingMode programmatically
+  void setAddressingMode(const AddressingMode addressingMode) {} 
+  
+private:
+  /* lcd control */
+  void reinit() {
+    i2c.deinit();
+    i2c.init(SH1106_I2C_SCL_CLOCK);
+    sendc(0xAF); //display on
+    sendc(inverted? 0xA7 : 0xA6); //inversion
+  }
+  
+  /* send bytes */
+  void sendc(const uint8_t cmd) {
+    i2c.start(SH1106_I2C_ADDR);
+    i2c.write(SH1106_COMMAND);
+    i2c.write(cmd);
+    i2c.stop();
+  }
+  void sendc(const uint8_t cmd1, const uint8_t cmd2) {
+    i2c.start(SH1106_I2C_ADDR);
+    i2c.write(SH1106_COMMAND);
+    i2c.write(cmd1);
+    i2c.write(cmd2);
+    i2c.stop();
+  }
+  void sendc(const uint8_t cmd1, const uint8_t cmd2, const uint8_t cmd3) {
+    i2c.start(SH1106_I2C_ADDR);
+    i2c.write(SH1106_COMMAND);
+    i2c.write(cmd1);
+    i2c.write(cmd2);
+    i2c.write(cmd3);
+    i2c.stop();
+  }
+  void sendd(const uint8_t* d, uint16_t sz) {  
+    const uint8_t blackPx = inverted? 0xFF : 0;
+    while(sz) {  //page cycle
+      sendc(0xB0 + page); //set page address to i (0..7)
+      sendc(0x00 + (col&0x0F)); //Sets 4 lower bits of column address 
+      sendc(0x10 + (col>>4)); //Sets 4 higher bits of column address 
+      
+      i2c.start(SH1106_I2C_ADDR);
+      i2c.write(SH1106_DATA);
+      while(sz) { //column cycle
+        i2c.write(*d++);
+        --sz;
+        if(++col >= SH1106_COLS_USED) {
+          while(col++ < SH1106_COLS_TOTAL) i2c.write(blackPx);
+          col = 0;
+          break;
+        }
+      }
+      i2c.stop();
+    
+      if(col == 0 && ++page >= SH1106_PAGES) page = 0;
+    }     
+  }
+
+  uint8_t col = 0;
+  uint8_t page = 0;
+  bool inverted = false;
+};
+
+
+#endif