Diff: main.cpp

Revision:

0:d5e1eec2689a

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Tue Jan 28 16:50:08 2014 +0000
@@ -0,0 +1,113 @@
+/*
+ * Allen Wild
+ * Joseph Guinta
+ *
+ * ECE 4180 Lab 1
+ */
+
+#include "mbed.h"
+#include "rtos.h"
+#include "MCP23S17.h"
+#include "ShiftBrite.h"
+
+#define PB0_PIN p20
+#define LED_PIN p29
+#define PWM_PIN p21
+#define EX_CS_PIN p18
+
+void updateSBColor(void const *args);
+
+DigitalIn pb1(PB0_PIN);
+DigitalOut led(LED_PIN);
+PwmOut pwm(PWM_PIN);
+
+SPI ex_spi(p11, p12, p13);
+MCP23S17 ex(ex_spi, EX_CS_PIN, 0x40);
+
+// flags set when reading/writing the SPI extender,
+// helpful for knowing what's happening in the logic analyzer
+DigitalOut ex_read(p24);
+DigitalOut ex_write(p23);
+
+ShiftBrite sb(p5, p6, p7, p8);
+const int sbcolors[] = {0xff0000, 0xffff00, 0x00ff00, 0x00ffff, 0x0000ff, 0xff00ff};
+int sbci = 0;
+
+// brightness of PWM output
+float bright = 0.0f;
+bool pb1p = false;
+
+int main()
+{
+    // set extender as inputs, configure internal pullups
+    ex.direction(PORT_A, 0xFF);
+    ex.configurePullUps(PORT_A, 0x90);
+    // port B as outputs (for LED)
+    ex.direction(PORT_B, 0x00);
+    
+    ex_read = 0;
+    ex_write = 0;
+
+    sb.writeInit(32, 0, 0);
+    sb.fadeColor(0, 0xff0000, 0.5);
+    
+    // set PWM to 100Hz
+    pwm.period_ms(10);
+
+    // oh no, I'm multithreading this
+    // god help us all...
+    Thread sbThread(updateSBColor);
+
+    while (true)
+    {
+        // read button and turn on LED if pressed
+        pb1p = !pb1;
+        led = pb1p;
+        if (pb1p)
+            sbThread.signal_set(0x1);
+        while (!pb1);
+
+        // use pushbuttons on extender to control PWM brightness
+        // invert because active-low switches
+        ex_read = 1;
+        char edata = ~(ex.read(PORT_A));
+        ex_read = 0;
+
+        // if either button pressed, turn on ex LED
+        if (edata & 0x90)
+        {
+            ex_write = 1; // note: debugging signal only
+            ex.write(PORT_B, 1);
+            ex_write = 0;
+        }
+        else
+        {
+            ex_write = 1;
+            ex.write(PORT_B, 0);
+            ex_write = 0;
+        }
+
+        // if button 1 and below max brightness, increment by 1%
+        if ((edata&0x80) && bright < 1.0)
+            bright += 0.01;
+        // likewise for button 2 to decrement
+        if ((edata&0x10) && bright > 0)
+            bright -= 0.01;
+        pwm = bright;
+
+        Thread::wait(10);
+    }
+}
+
+// SB color fading happens in a different thread
+void updateSBColor(void const *args)
+{
+    while (true)
+    {
+        //Thread::wait(100);
+        Thread::signal_wait(0x1);
+        sb.fadeColor(sbcolors[(sbci != 0) ? sbci-1 : 5], sbcolors[sbci], 0.5);
+        if (++sbci > 5)
+            sbci = 0;
+    }
+}
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