Diff: dtest.cpp

Revision:

0:38ecd3d98f79

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dtest.cpp	Mon Sep 28 08:15:28 2015 +0000
@@ -0,0 +1,139 @@
+/*
+ *  dtest.cpp -- driving test for CO657
+ *  Copyright (C) 2015 Fred Barnes, University of Kent  <frmb@kent.ac.uk>
+ *  GPL >= 2.0
+ */
+
+#include "mbed.h"                       /* stock MBED API */
+
+/* assorted globals */
+
+DigitalOut r_led (LED1);                /* connections for RGB LED */
+DigitalOut g_led (LED2);
+DigitalOut b_led (LED3);
+
+Serial host (USBTX, USBRX);             /* to-host UART via OpenSDAv2 */
+
+InterruptIn sw2_int (PTC6);             /* interrupts for the two on-board switches */
+InterruptIn sw3_int (PTA4);
+
+Ticker rgb_tick;                        /* timer for driving the LED */
+
+static volatile uint16_t counters[3];   /* red, green, blue */
+static volatile uint8_t bright[3];
+
+static volatile int sw2_trig;           /* switches triggered? */
+static volatile int sw3_trig;
+
+
+/*
+ *  turns offset [0-311] into brightness level [0-255-255-0].
+ */
+uint8_t brilvl (int offset)
+{
+    while (offset > 311) {
+        offset -= 312;
+    }
+    if (offset < 52) {
+        return (uint8_t)(offset * 5);
+    } else if (offset < 156) {
+        return 255;
+    } else if (offset < 208) {
+        return (uint8_t)((207 - offset) * 5);
+    }
+    return 0;
+}
+
+
+/*
+ *  resets the various counters to their initial state
+ */
+void reset_counters (void)
+{
+    for (int i=0; i<3; i++) {
+        counters[i] = 0;
+        bright[i] = brilvl (i * 104);
+    }
+}
+
+
+/*
+ *  interrupt handlers
+ */
+void rgb_tick_interrupt (void)
+{
+    for (int i=0; i<3; i++) {
+        counters[i] += (uint16_t)bright[i];
+    }
+    
+    r_led = ((counters[0] >> 8) & 1) ^ 1;
+    g_led = ((counters[1] >> 8) & 1) ^ 1;
+    b_led = ((counters[2] >> 8) & 1) ^ 1;
+    
+    for (int i=0; i<3; i++) {
+        counters[i] &= 0xff;
+    }
+}
+
+
+void sw2_interrupt (void)
+{
+    sw2_trig = 1;
+}
+
+
+void sw3_interrupt (void)
+{
+    sw3_trig = 1;
+}
+
+
+
+
+/*
+ *  start here
+ */
+int main (void)
+{
+    int ctr;
+    
+    host.baud (38400);
+    host.printf ("Hello, FRDM-K64F driving-test world!\r\n");
+    
+    sw2_trig = 0;
+    sw3_trig = 0;
+    
+    reset_counters ();
+    
+    rgb_tick.attach (&rgb_tick_interrupt, 0.001);
+    ctr = 0;
+    
+    sw2_int.mode (PullUp);
+    sw2_int.fall (&sw2_interrupt);
+    
+    sw3_int.mode (PullUp);
+    sw3_int.fall (&sw3_interrupt);
+    
+    /* and then forever.. */
+    for (;;) {
+        wait (0.02);
+        
+        if (sw2_trig) {
+            ctr += 104;
+            sw2_trig = 0;
+        }
+        if (sw3_trig) {
+            ctr += 208;
+            sw3_trig = 0;
+        }
+        
+        ctr++;
+        if (ctr > 311) {
+            ctr -= 312;
+        }
+        for (int i=0; i<3; i++) {
+            bright[i] = brilvl (ctr + (i * 104));
+        }
+    }
+}
+