Diff: main.cpp

Revision:

0:0a76ae27065b

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Wed May 05 12:10:15 2010 +0000
@@ -0,0 +1,123 @@
+/*
+mbed touchpad & accelerometer experiments.
+
+CPV, 14/09/2009
+*/
+
+#include "mbed.h"
+#include "touchpad.h"
+#include "accelerometer.h"
+#include "my_pwm_out.h"
+
+
+// Pin definitions.
+#define ACC0  p20
+#define ACC1  p19
+#define X0  p18
+#define Y0  p17
+#define X1  p16
+#define Y1  p15
+
+
+// Some global objects.
+DigitalOut led1(LED1);
+Ticker timer1; // Sample clock.
+Ticker timer2; // "keyboard" scan clock.
+Ticker timer3; // LED clock.
+Touchpad tp(X0,X1,Y0,Y1);
+Accelerometer2D acc(ACC0,ACC1,10);
+MyPwmOut buzzer(p21); // Subclassed from PwmOut.
+
+
+float DutyCycle = 0.0; // No sound.
+int Period = 1136; // in us => 880 Hz.
+int FlagUpdateSound = 0;
+
+// Periods in us.
+const int freq[4][6] = 
+{
+  { 1607, 1517, 1432, 1351, 1276, 1204 },
+  { 1136, 1073, 1012, 956, 902, 851 },
+  { 804, 758, 716, 676, 638, 602 },
+  { 568, 536, 506, 478, 451, 426 },
+};
+
+
+void sample(void)
+{
+  tp.tick();
+  acc.tick();
+}
+
+
+void scan_keyboard(void)
+{
+  if (tp.hotspot()>0)
+  {
+    int x = tp.get_hotspot_x();
+    int y = tp.get_hotspot_y();
+    Period = freq[y][x]*(1.0+acc.read(0)/64000.0);
+    DutyCycle = 0.5 + acc.read(1)/32000.0;
+    FlagUpdateSound = 1;
+  }
+  else
+  {
+    if (DutyCycle!=0.0) 
+    {
+      DutyCycle = 0.0;
+      FlagUpdateSound = 1;
+    }
+  }
+}
+
+
+void toggle_led(void)
+{
+  if (led1==1) led1 = 0;
+  else led1 = 1;
+}
+
+
+int main() 
+{
+  printf("\n");
+  printf("-=o Touch, Shake & Whine o=-\n");
+  printf("\n");
+  printf("mbed touchpad & 2D accelerometer demo\n");
+  printf("\n");
+  printf("A buzzer is driven by a PWM signal to generate musical notes.\n");
+  printf("A touchpad is used as a keypad, divided in a 6 by 4 matrix.\n");
+  printf("The position on the touchpad determines the note played by the\n");
+  printf("buzzer. A 2-axis accelerometer is used to modulate the frequency\n");
+  printf("and the duty-cycle of the PWM signal.\n");
+  printf("A blinking LED shows that the system is running.\n");
+  printf("\n");
+  printf("Touch & shake the circuit to make it whine.\n");
+  printf("\n");
+  printf("Demonstrates:\n");
+  printf("- the use of a resistive touchpad\n");
+  printf("- the use of a 2D accelerometer\n");
+  printf("- the use of PWM for smooth frequency generation\n");
+  printf("- on-the-fly pin function switching\n");
+  printf("- mbed \"base\" class extension\n");
+  printf("\n");
+  printf("CPV, 14/09/2009\n");
+  printf("\n");
+  printf("     -end-\n\n");
+  
+  led1 = 1; // LED on.
+  
+  timer1.attach_us(&sample,1000); // Sample every 1 ms.
+  timer2.attach_us(&scan_keyboard,10000); // Scan the touchpad every 10 ms.
+  timer3.attach_us(&toggle_led,500000); // Toggle the LED every 500 ms.
+
+  while (1)
+  {
+    if (FlagUpdateSound==1)
+    {
+      // Only update period & duty-cycle when new data is available.
+      FlagUpdateSound = 0;
+      buzzer.set(Period/1000000.0,DutyCycle);
+    }
+  }
+}