SSD1306_SPI.cpp

00001 /* NeatGUI Library
00002  * Copyright (c) 2013 Neil Thiessen
00003  *
00004  * Licensed under the Apache License, Version 2.0 (the "License");
00005  * you may not use this file except in compliance with the License.
00006  * You may obtain a copy of the License at
00007  *
00008  *     http://www.apache.org/licenses/LICENSE-2.0
00009  *
00010  * Unless required by applicable law or agreed to in writing, software
00011  * distributed under the License is distributed on an "AS IS" BASIS,
00012  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00013  * See the License for the specific language governing permissions and
00014  * limitations under the License.
00015  */
00016 
00017 #include "SSD1306_SPI.h"
00018 
00019 SSD1306_SPI::SSD1306_SPI(PinName mosi, PinName miso, PinName sclk, PinName cs, PinName dc) : Display(128, 64), m_SPI(mosi, miso, sclk), m_CS(cs), m_DC(dc)
00020 {
00021     //Deselect the display
00022     m_CS = 1;
00023 
00024     //Set the SPI format to 8 bit data, high steady state clock, second edge capture
00025     m_SPI.format(8, 3);
00026 
00027     //Set the SPI frequency to 10MHz
00028     m_SPI.frequency(10000000);
00029 }
00030 
00031 bool SSD1306_SPI::open()
00032 {
00033     //Init sequence for 128x64 OLED module
00034     writeCommand(CMD_DISPLAYOFF);
00035     writeCommand(CMD_SETDISPLAYCLOCKDIV);
00036     writeCommand(0x80);
00037     writeCommand(CMD_SETMULTIPLEX);
00038     writeCommand(0x3F);
00039     writeCommand(CMD_SETDISPLAYOFFSET);
00040     writeCommand(0x0);
00041     writeCommand(CMD_SETSTARTLINE | 0x0);
00042     writeCommand(CMD_CHARGEPUMP);
00043     writeCommand(CMD_CHARGEPUMPON);
00044     writeCommand(CMD_MEMORYMODE);
00045     writeCommand(0x00);
00046     writeCommand(CMD_SEGREMAP | 0x1);
00047     writeCommand(CMD_COMSCANDEC);
00048     writeCommand(CMD_SETCOMPINS);
00049     writeCommand(0x12);
00050     writeCommand(CMD_SETCONTRAST);
00051     writeCommand(0xCF);
00052     writeCommand(CMD_SETPRECHARGE);
00053     writeCommand(0xF1);
00054     writeCommand(CMD_SETVCOMDETECT);
00055     writeCommand(0x40);
00056     writeCommand(CMD_DISPLAYALLON_RESUME);
00057     writeCommand(CMD_NORMALDISPLAY);
00058 
00059     //Return success
00060     return true;
00061 }
00062 
00063 void SSD1306_SPI::flush()
00064 {
00065     //Select low col 0, hi col 0, line 0
00066     writeCommand(CMD_SETLOWCOLUMN | 0x0);
00067     writeCommand(CMD_SETHIGHCOLUMN | 0x0);
00068     writeCommand(CMD_SETSTARTLINE | 0x0);
00069 
00070     //Set DC to data and select the chip
00071     m_DC = 1;
00072     m_CS = 0;
00073 
00074     //Write the entire buffer at once
00075     for (int i = 0; i < 1024; i++)
00076         m_SPI.write(m_Buffer[i]);
00077 
00078     //Deselect the chip
00079     m_CS = 1;
00080 }
00081 
00082 Display::State SSD1306_SPI::state()
00083 {
00084     //Return the base class's state
00085     return Display::state();
00086 }
00087 
00088 void SSD1306_SPI::state(State s)
00089 {
00090     //Check what the requested state is
00091     if (s == Display::DISPLAY_ON) {
00092         //Turn the display on
00093         writeCommand(CMD_DISPLAYON);
00094     } else if (s == Display::DISPLAY_OFF) {
00095         //Turn the display off
00096         writeCommand(CMD_DISPLAYOFF);
00097     }
00098 
00099     //Update the base class
00100     Display::state(s);
00101 }
00102 
00103 void SSD1306_SPI::drawPixel(int x, int y, unsigned int c)
00104 {
00105     //Range check the pixel
00106     if ((x < 0) || (x >= width()) || (y < 0) || (y >= height()))
00107         return;
00108 
00109     //Make sure the color is fully opaque
00110     if ((c >> 24) != 255)
00111         return;
00112 
00113     //Determine the pixel byte index
00114     unsigned short byteIndex = x + (y / 8) * width();
00115 
00116     //Set or clear the pixel
00117     if ((c & 0x00FFFFFF) > 0)
00118         m_Buffer[byteIndex] |= (1 << (y % 8));
00119     else
00120         m_Buffer[byteIndex] &= ~(1 << (y % 8));
00121 }
00122 
00123 void SSD1306_SPI::writeCommand(char command)
00124 {
00125     //Set DC to command and select the display
00126     m_DC = 0;
00127     m_CS = 0;
00128 
00129     //Write the command byte
00130     m_SPI.write(command);
00131 
00132     //Deselect the display
00133     m_CS = 1;
00134 }
00135 
00136 void SSD1306_SPI::writeData(char data)
00137 {
00138     //Set DC to data and select the display
00139     m_DC = 1;
00140     m_CS = 0;
00141 
00142     //Write the data byte
00143     m_SPI.write(data);
00144 
00145     //Deselect the display
00146     m_CS = 1;
00147 }