Merge pull request #26 from neptune2/master

Added support for SPI version of OLED display

Author: squix78

README.md

@@ -1,12 +1,14 @@
 # esp8266-oled-ssd1306
 
 This is a driver for the SSD1306 based 128x64 pixel OLED display running on the Arduino/ESP8266 platform.
+Can be used with either the I2C or SPI version of the display
 
 You can either download this library as a zip file and unpack it to your Arduino/libraries folder or (once it has been added) choose it from the Arduino library manager.
 
 ## Credits
 Many thanks go to Fabrice Weinberg (@FWeinb) for optimizing and refactoring the UI library.
 The init sequence for the SSD1306 was inspired by Adafruits library for the same display.
+The SPI code was inspired by somhi/ESP_SSD1306 and the Adafruit library
 
 ## Usage
 
@@ -187,3 +189,9 @@ This frame demonstrates the text alignment. The coordinates in the frame show re
 ![DemoFrame4](https://github.com/squix78/esp8266-oled-ssd1306/raw/master/resources/DemoFrame4.jpg)
 
 This shows how to use define a maximum width after which the driver automatically wraps a word to the next line. This comes in very handy if you have longer texts to display.
+
+### SPI version
+
+![SPIVersion](https://github.com/neptune2/esp8266-oled-ssd1306/raw/master/resources/SPI_version.jpg)
+
+This shows the code working on the SPI version of the display. See demo code for ESP8266 pins used.

SSD1306.cpp

@@ -23,21 +23,48 @@ SOFTWARE.
 See more at http://blog.squix.ch
 
 Credits for parts of this code go to Mike Rankin. Thank you so much for sharing!
+
+SPI additions by Neptune2
 */
 
 #include "SSD1306.h"
-#include <Wire.h>
-
 
+// constructor for I2C - we indicate i2cAddress, sda and sdc
 SSD1306::SSD1306(int i2cAddress, int sda, int sdc) {
   myI2cAddress = i2cAddress;
   mySda = sda;
   mySdc = sdc;
+  I2C_io = true;
+}
+
+// constructor for hardware SPI - we indicate Reset, DataCommand and ChipSelect 
+// (HW_SPI used to differentiate constructor - reserved for future use)
+SSD1306::SSD1306(bool HW_SPI, int rst, int dc, int cs ) {
+  myRST = rst;
+  myDC = dc;
+  myCS = cs;
+  I2C_io = false;
 }
 
 void SSD1306::init() {
-  Wire.begin(mySda, mySdc);
-  Wire.setClock(400000);
+  if (I2C_io){
+   Wire.begin(mySda, mySdc);
+   Wire.setClock(400000);
+  } else {
+   pinMode(myDC, OUTPUT);
+   pinMode(myCS, OUTPUT);
+
+   SPI.begin ();
+   SPI.setClockDivider (SPI_CLOCK_DIV2);
+
+   pinMode(myRST, OUTPUT);
+   // Pulse Reset low for 10ms
+   digitalWrite(myRST, HIGH);
+   delay(1);
+   digitalWrite(myRST, LOW);
+   delay(10);
+   digitalWrite(myRST, HIGH);
+  }
   sendInitCommands();
   resetDisplay();
 }
@@ -50,7 +77,11 @@ void SSD1306::resetDisplay(void) {
 }
 
 void SSD1306::reconnect() {
-  Wire.begin(mySda, mySdc);
+  if (I2C_io){
+   Wire.begin(mySda, mySdc);
+  } else {
+   SPI.begin ();
+  }
 }
 
 void SSD1306::displayOn(void) {
@@ -84,6 +115,8 @@ void SSD1306::display(void) {
     sendCommand(0x0);
     sendCommand(0x7);
 
+	
+  if (I2C_io) {
     for (uint16_t i=0; i<(128*64/8); i++) {
       // send a bunch of data in one xmission
       Wire.beginTransmission(myI2cAddress);
@@ -96,8 +129,15 @@ void SSD1306::display(void) {
       yield();
       Wire.endTransmission();
     }
-
-
+  }	else {
+	digitalWrite(myCS, HIGH);
+    digitalWrite(myDC, HIGH);   // data mode
+    digitalWrite(myCS, LOW);
+	for (uint16_t i=0; i<(128*64/8); i++) {
+	 SPI.transfer(buffer[i]);
+	}
+	digitalWrite(myCS, HIGH);	
+  }
 }
 
 void SSD1306::setPixel(int x, int y) {
@@ -316,10 +356,18 @@ void SSD1306::drawXbm(int x, int y, int width, int height, const char *xbm) {
 }
 
 void SSD1306::sendCommand(unsigned char com) {
-  Wire.beginTransmission(myI2cAddress);     //begin transmitting
-  Wire.write(0x80);                          //command mode
-  Wire.write(com);
-  Wire.endTransmission();                    // stop transmitting
+  if (I2C_io) {
+   Wire.beginTransmission(myI2cAddress);      //begin transmitting
+   Wire.write(0x80);                          //command mode
+   Wire.write(com);
+   Wire.endTransmission();                    // stop transmitting
+  } else {
+   digitalWrite(myCS, HIGH);
+   digitalWrite(myDC, LOW);                     //command mode
+   digitalWrite(myCS, LOW);
+   SPI.transfer(com);
+   digitalWrite(myCS, HIGH);
+  }
 }
 
 void SSD1306::sendInitCommands(void) {

SSD1306.h

@@ -27,6 +27,8 @@ Credits for parts of this code go to Mike Rankin. Thank you so much for sharing!
 #pragma once
 
 #include <Arduino.h>
+#include <Wire.h>
+#include <SPI.h>
 #include "SSD1306Fonts.h"
 
 #define BLACK 0
@@ -73,19 +75,28 @@ Credits for parts of this code go to Mike Rankin. Thank you so much for sharing!
 class SSD1306 {
 
 private:
+   // I2C
    int myI2cAddress;
    int mySda;
    int mySdc;
+   bool I2C_io;
+
+   // SPI
+   int  myDC, myRST, myCS;
+   
    uint8_t buffer[128 * 64 / 8];
    int myTextAlignment = TEXT_ALIGN_LEFT;
    int myColor = WHITE;
    byte lastChar;
    const char *myFontData = ArialMT_Plain_10;
 
 public:
-   // Create the display object connected to pin sda and sdc
+   // Create the display object connected to I2C pins pin sda and sdc
    SSD1306(int i2cAddress, int sda, int sdc);
 
+   // Create the display object connected to SPI pins and rst, dc and cs (HW_SPI reserved for future use)
+   SSD1306(bool HW_SPI, int rst, int dc, int cs );
+   
    // Initialize the display
    void init();
 

examples/SSD1306Demo/SSD1306Demo.ino

@@ -23,13 +23,33 @@ SOFTWARE.
 See more at http://blog.squix.ch
 */
 #include <Wire.h>
+#include <SPI.h>
 #include "SSD1306.h"
 #include "SSD1306Ui.h"
 #include "images.h"
 
-// Initialize the oled display for address 0x3c
-// sda-pin=14 and sdc-pin=12
-SSD1306   display(0x3c, D3, D4);
+// Pin definitions for I2C
+#define OLED_SDA    D2  // pin 14
+#define OLED_SDC    D4  // pin 12
+#define OLED_ADDR   0x3C
+
+/* Hardware Wemos D1 mini SPI pins
+ D5 GPIO14   CLK         - D0 pin OLED display
+ D6 GPIO12   MISO (DIN)  - not connected
+ D7 GPIO13   MOSI (DOUT) - D1 pin OLED display
+ D8 GPIO15   CS / SS     - CS pin OLED display
+ D0 GPIO16   RST         - RST pin OLED display
+ D2 GPIO4    DC          - DC pin OLED
+*/
+
+// Pin definitions for SPI
+#define OLED_RESET  D0  // RESET
+#define OLED_DC     D2  // Data/Command
+#define OLED_CS     D8  // Chip select
+
+// Uncomment one of the following based on OLED type
+// SSD1306 display(true, OLED_RESET, OLED_DC, OLED_CS); // FOR SPI
+SSD1306   display(OLED_ADDR, OLED_SDA, OLED_SDC);    // For I2C
 SSD1306Ui ui     ( &display );
 
 // this array keeps function pointers to all frames

library.json

@@ -18,5 +18,5 @@
   ],
   "frameworks": "arduino",
   "platforms": "espressif",
-  "version": "2.0.1"
+  "version": "2.0.2"
 }

library.properties

@@ -1,5 +1,5 @@
 name=ESP8266 Oled Driver for SSD1306 display
-version=2.0.0
+version=2.0.2
 author=Daniel Eichhorn, Fabrice Weinberg
 maintainer=Daniel Eichhorn <squix78@gmail.com>
 sentence=A display driver for SSD1306 oled displays connected to an ESP8266