added GUI usage demo

demos/gui/main.c

@@ -0,0 +1,74 @@
+#include "ch.h"
+#include "hal.h"
+#include "gui.h"
+#include "glcd.h"
+#include "touchpad.h"
+
+__inline void lld_lcdWriteGPIO(uint16_t data) {
+	palWritePort(LCD_DATA_PORT, data);
+}
+
+__inline uint16_t lld_lcdReadGPIO(void) {
+	uint16_t value;
+
+    // change pin mode to digital input
+    LCD_DATA_PORT->CRH = 0x44444444;
+    LCD_DATA_PORT->CRL = 0x44444444;
+
+    value = palReadPort(LCD_DATA_PORT); // dummy
+    value = palReadPort(LCD_DATA_PORT);
+
+    // change pin mode back to digital output
+    LCD_DATA_PORT->CRH = 0x33333333;
+    LCD_DATA_PORT->CRL = 0x33333333;
+
+	return value;
+}
+
+// GLCD driver object
+static GLCDDriver GLCDD1;
+
+int main(void) {
+	uint8_t setActive, setState, clearActive, clearState;
+
+	halInit();
+	chSysInit();
+
+	// Initializes the LCD
+    lcdInit(&GLCDD1);
+
+	// Initializes the touchpad
+	tpInit(&SPID1);
+
+	// clear the entire LCD screen
+    lcdClear(Black);
+
+	// Initializes the GUI thread
+	// 10ms interval
+	// HIGHPRIO-2 thread priority level
+	guiInit(10, HIGHPRIO-2);
+
+	// set the following buttons to active
+	// buttons wouldn't have any effect if you set these variables to 'inactive'
+	setActive = active;
+	clearActive = active;
+	
+	// draw a button to set, and one to clear the LED
+	guiDrawButton(10, 10, 60, 60, "Set", Black, Yellow, &setActive, &setState);
+	guiDrawButton(70, 10, 120, 60, "Clear", Black, Red, &clearActive, &clearState);
+	
+	while (TRUE) {
+
+		// check if button 'set' is pressed
+		if(setState)
+			palSetPad(GPIOD, GPIOD_LED3);
+
+		// check if button 'clear' is pressed
+		if(clearState)
+			palClearPad(GPIOD, GPIOD_LED3);
+	
+		chThdSleepMilliseconds(200);	
+	}
+
+	return 0;
+}