Implements support for SH1106 SPI

Author: FWeinb

SH1106Spi.h

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+/**
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2016 by Daniel Eichhorn
+ * Copyright (c) 2016 by Fabrice Weinberg
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * Credits for parts of this code go to Mike Rankin. Thank you so much for sharing!
+ */
+
+#ifndef SH1106Spi_h
+#define SH1106Spi_h
+
+#include "OLEDDisplay.h"
+#include <SPI.h>
+
+class SH1106Spi : public OLEDDisplay {
+  private:
+      uint8_t             _rst;
+      uint8_t             _dc;
+
+  public:
+
+    SH1106Spi(uint8_t _rst, uint8_t _dc) {
+      this->_rst = _rst;
+      this->_dc  = _dc;
+    }
+
+    bool connect(){
+      pinMode(_dc, OUTPUT);
+      pinMode(_rst, OUTPUT);
+
+      SPI.begin ();
+      SPI.setClockDivider (SPI_CLOCK_DIV2);
+
+      // Pulse Reset low for 10ms
+      digitalWrite(_rst, HIGH);
+      delay(1);
+      digitalWrite(_rst, LOW);
+      delay(10);
+      digitalWrite(_rst, HIGH);
+      return true;
+    }
+
+    void display(void) {
+    #ifdef OLEDDISPLAY_DOUBLE_BUFFER
+       uint8_t minBoundY = ~0;
+       uint8_t maxBoundY = 0;
+
+       uint8_t minBoundX = ~0;
+       uint8_t maxBoundX = 0;
+
+       uint8_t x, y;
+
+       // Calculate the Y bounding box of changes
+       // and copy buffer[pos] to buffer_back[pos];
+       for (y = 0; y < (DISPLAY_HEIGHT / 8); y++) {
+         for (x = 0; x < DISPLAY_WIDTH; x++) {
+          uint16_t pos = x + y * DISPLAY_WIDTH;
+          if (buffer[pos] != buffer_back[pos]) {
+            minBoundY = _min(minBoundY, y);
+            maxBoundY = _max(maxBoundY, y);
+            minBoundX = _min(minBoundX, x);
+            maxBoundX = _max(maxBoundX, x);
+          }
+          buffer_back[pos] = buffer[pos];
+        }
+        yield();
+       }
+
+       // If the minBoundY wasn't updated
+       // we can savely assume that buffer_back[pos] == buffer[pos]
+       // holdes true for all values of pos
+       if (minBoundY == ~0) return;
+
+       // Calculate the colum offset
+       uint8_t minBoundXp2H = (minBoundX + 2) & 0x0F;
+       uint8_t minBoundXp2L = 0x10 | ((minBoundX + 2) >> 4 );
+
+       for (y = minBoundY; y <= maxBoundY; y++) {
+         sendCommand(0xB0 + y);
+         sendCommand(minBoundXp2H);
+         sendCommand(minBoundXp2L);
+         digitalWrite(_dc, HIGH);   // data mode
+         for (x = minBoundX; x <= maxBoundX; x++) {
+           SPI.transfer(buffer[x + y * DISPLAY_WIDTH]);
+         }
+         yield();
+       }
+     #else
+      for (uint8_t y=0; y<DISPLAY_HEIGHT/8; y++) {
+        sendCommand(0xB0 + y);
+        sendCommand(0x02);
+        sendCommand(0x10);
+        digitalWrite(_dc, HIGH);   // data mode
+        for( uint8_t x=0; x < DISPLAY_WIDTH; x++) {
+          SPI.transfer(buffer[x + y * DISPLAY_WIDTH]);
+        }
+        yield();
+      }
+     #endif
+    }
+
+  private:
+    inline void sendCommand(uint8_t com) __attribute__((always_inline)){
+      digitalWrite(_dc, LOW);
+      SPI.transfer(com);
+    }
+};
+
+#endif