main.cpp

00001 #include "mbed.h"
00002 #include "Adafruit_SSD1306.h"
00003 
00004 //Switch input definition
00005 #define SW_PIN p22
00006 
00007 //Sampling period for the switch oscillator (us)
00008 #define SW_PERIOD 20000 
00009 
00010 //Display interface pin definitions
00011 #define D_MOSI_PIN p5
00012 #define D_CLK_PIN p7
00013 #define D_DC_PIN p8
00014 #define D_RST_PIN p9
00015 #define D_CS_PIN p10
00016 
00017 //an SPI sub-class that sets up format and clock speed
00018 class SPIPreInit : public SPI
00019 {
00020 public:
00021     SPIPreInit(PinName mosi, PinName miso, PinName clk) : SPI(mosi,miso,clk)
00022     {
00023         format(8,3);
00024         frequency(2000000);
00025     };
00026 };
00027 
00028 //Interrupt Service Routine prototypes (functions defined below)
00029 void sedge();
00030 void tout();
00031 
00032 //Output for the alive LED
00033 DigitalOut alive(LED1);
00034 
00035 //External interrupt input from the switch oscillator
00036 InterruptIn swin(SW_PIN);
00037 
00038 //Switch sampling timer
00039 Ticker swtimer;
00040 
00041 //Registers for the switch counter, switch counter latch register and update flag
00042 volatile uint16_t scounter=0;
00043 volatile uint16_t scount=0;
00044 volatile uint16_t update=0;
00045 
00046 //Initialise SPI instance for communication with the display
00047 SPIPreInit gSpi(D_MOSI_PIN,NC,D_CLK_PIN); //MOSI,MISO,CLK
00048 
00049 //Initialise display driver instance
00050 Adafruit_SSD1306_Spi gOled1(gSpi,D_DC_PIN,D_RST_PIN,D_CS_PIN,64,128); //SPI,DC,RST,CS,Height,Width
00051 
00052 int main() { 
00053     //Initialisation
00054     gOled1.setRotation(2); //Set display rotation
00055     
00056     //Attach switch oscillator counter ISR to the switch input instance for a rising edge
00057     swin.rise(&sedge);
00058     
00059     //Attach switch sampling timer ISR to the timer instance with the required period
00060     swtimer.attach_us(&tout, SW_PERIOD);
00061     
00062     //Write some sample text
00063     gOled1.printf("%ux%u OLED Display\r\n", gOled1.width(), gOled1.height());
00064     
00065     //Main loop
00066     while(1)
00067     {
00068         //Has the update flag been set?       
00069         if (update) {
00070             //Clear the update flag
00071             update = 0;
00072             
00073             //Set text cursor
00074             gOled1.setTextCursor(0,0);
00075             
00076             //Write the latest switch osciallor count
00077             gOled1.printf("\n%05u  ",scount);
00078             
00079             //Copy the display buffer to the display
00080             gOled1.display();
00081             
00082             //Toggle the alive LED
00083             alive = !alive;
00084         }
00085         
00086         
00087     }
00088 }
00089 
00090 
00091 //Interrupt Service Routine for rising edge on the switch oscillator input
00092 void sedge() {
00093     //Increment the edge counter
00094     scounter++;    
00095 }
00096 
00097 //Interrupt Service Routine for the switch sampling timer
00098 void tout() {
00099     //Read the edge counter into the output register
00100     scount = scounter;
00101     //Reset the edge counter
00102     scounter = 0;
00103     //Trigger a display update in the main loop
00104     update = 1;
00105 }
00106