1 files changed, 104 insertions, 0 deletions
diff --git a/src/switch.cpp b/src/switch.cpp
new file mode 100644
index 0000000..2381640
--- /dev/null
+++ b/src/switch.cpp
@@ -0,0 +1,104 @@
+#include "mbed.h"
+#include "Adafruit_SSD1306.h"
+
+//Switch input definition
+#define SW_PIN p22
+
+//Sampling period for the switch oscillator (us)
+#define SW_PERIOD 20000
+
+//Display interface pin definitions
+#define D_MOSI_PIN p5
+#define D_CLK_PIN p7
+#define D_DC_PIN p8
+#define D_RST_PIN p9
+#define D_CS_PIN p10
+
+//an SPI sub-class that sets up format and clock speed
+class SPIPreInit:public SPI {
+ public:
+	SPIPreInit(PinName mosi, PinName miso, PinName clk):SPI(mosi, miso, clk) {
+		format(8, 3);
+		frequency(2000000);
+	};
+};
+
+//Interrupt Service Routine prototypes (functions defined below)
+void sedge();
+void tout();
+
+//Output for the alive LED
+DigitalOut alive(LED1);
+
+//External interrupt input from the switch oscillator
+InterruptIn swin(SW_PIN);
+
+//Switch sampling timer
+Ticker swtimer;
+
+//Registers for the switch counter, switch counter latch register and update flag
+volatile uint16_t scounter = 0;
+volatile uint16_t scount = 0;
+volatile uint16_t update = 0;
+
+//Initialise SPI instance for communication with the display
+SPIPreInit gSpi(D_MOSI_PIN, NC, D_CLK_PIN);	//MOSI,MISO,CLK
+
+//Initialise display driver instance
+Adafruit_SSD1306_Spi gOled1(gSpi, D_DC_PIN, D_RST_PIN, D_CS_PIN, 64, 128);	//SPI,DC,RST,CS,Height,Width
+
+int main()
+{
+	//Initialisation
+	gOled1.setRotation(2);	//Set display rotation
+
+	//Attach switch oscillator counter ISR to the switch input instance for a rising edge
+	swin.rise(&sedge);
+
+	//Attach switch sampling timer ISR to the timer instance with the required period
+	swtimer.attach_us(&tout, SW_PERIOD);
+
+	//Write some sample text
+	gOled1.printf("%ux%u OLED Display\r\n", gOled1.width(),
+		      gOled1.height());
+
+	//Main loop
+	while (1) {
+		//Has the update flag been set?       
+		if (update) {
+			//Clear the update flag
+			update = 0;
+
+			//Set text cursor
+			gOled1.setTextCursor(0, 0);
+
+			//Write the latest switch osciallor count
+			gOled1.printf("\n%05u  ", scount);
+
+			//Copy the display buffer to the display
+			gOled1.display();
+
+			//Toggle the alive LED
+			alive = !alive;
+		}
+
+	}
+}
+
+//Interrupt Service Routine for rising edge on the switch oscillator input
+void sedge()
+{
+	//Increment the edge counter
+	scounter++;
+}
+
+//Interrupt Service Routine for the switch sampling timer
+void tout()
+{
+	//Read the edge counter into the output register
+	scount = scounter;
+	//Reset the edge counter
+	scounter = 0;
+	//Trigger a display update in the main loop
+	update = 1;
+}