Diff: main.cpp

Revision:

0:e8be38c50b44

Child:

1:81b129bec569

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Wed Jan 06 12:08:57 2016 +0000
@@ -0,0 +1,93 @@
+/* 
+
+2645_Ticker
+
+Sample code from ELEC2645 Week 16 Lab
+
+Demonstrates how to implement a simple FSM counter
+
+(c) Craig A. Evans, University of Leeds, Jan 2016
+
+*/ 
+
+#include "mbed.h"
+
+// K64F on-board LEDs 
+DigitalOut r_led(LED_RED);
+DigitalOut g_led(LED_GREEN);
+DigitalOut b_led(LED_BLUE);
+// K64F on-board switches
+InterruptIn sw2(SW2);
+InterruptIn sw3(SW3);
+
+// LEDs to display counter output
+// connect up external LEDs to these pins with appropriate current-limiting resistor
+BusOut output(PTB2,PTB3,PTB10,PTB11);
+
+// array of states in the FSM, each element is the output of the counter
+int fsm[4] = {1,2,4,8};
+
+// function prototypes
+// error function hangs flashing an LED
+void error();
+// set-up the on-board LEDs and switches
+void init_K64F();
+
+int main()
+{
+    init_K64F();
+    // set inital state 
+    int state = 0;
+
+    while(1) {  // loop forever
+
+        output = fsm[state];  // output current state
+
+        // check which state we are in and see which the next state should be
+        switch(state) {
+            case 0:
+                state = 1;
+                break;
+            case 1:
+                state = 2;
+                break;
+            case 2:
+                state = 3;
+                break;
+            case 3:
+                state = 0;
+                break;
+            default:
+                error();  //invalid state - call error routine
+                // or could jump to starting state i.e. state = 0
+                break;  
+        }
+
+        wait(0.2);  // small delay
+
+    }
+}
+
+void init_K64F() 
+{
+    // on-board LEDs are active-low, so set pin high to turn them off.
+    r_led = 1;
+    g_led = 1;
+    b_led = 1;   
+    
+    // since the on-board switches have external pull-ups, we should disable the internal pull-down
+    // resistors that are enabled by default using InterruptIn
+    sw2.mode(PullNone);
+    sw3.mode(PullNone);
+
+}
+
+void error()
+{
+    while(1) {  // if error, hang while flashing error message
+        r_led = 0;
+        wait(0.2);
+        r_led = 1;
+        wait(0.2);    
+    }    
+}
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