Diff: main.cpp

Revision:

1:fb324de02b7f

Parent:

0:c5278b91719f

--- a/main.cpp	Thu Jan 07 10:00:24 2016 +0000
+++ b/main.cpp	Wed Dec 20 11:53:00 2017 +0000
@@ -2,7 +2,7 @@
 
 2645_FSM_UpDown_Counter
 
-Sample code from ELEC2645 Week 16 Lab
+Sample code from ELEC2645
 
 Demonstrates how to implement a simple FSM up/down counter
 
@@ -25,35 +25,36 @@
 // K64F on-board switches
 InterruptIn sw2(SW2);
 InterruptIn sw3(SW3);
+// Gamepad Button A
+InterruptIn buttonA(PTB9);
 
-// LEDs to display counter output
-// connect up external LEDs to these pins with appropriate current-limiting resistor
-BusOut output(PTB2,PTB3,PTB10,PTB11);
+// LEDs on Gamepad (1 to 4) - active-low 0 = on and 1 = off
+BusOut output(PTA1,PTA2,PTC2,PTC3);
 
 // array of states in the FSM, each element is the output of the counter
-int fsm[4] = {1,2,4,8};
+// set the output in binary to make it easier, 0 is LED on, 1 is LED off
+int fsm[4] = {0b0111,0b1011,0b1101,0b1110};
 
 // flag - must be volatile as changes within ISR
 // g_ prefix makes it easier to distinguish it as global
-volatile int g_sw2_flag = 0;
+volatile int g_buttonA_flag = 0;
 
 // function prototypes
-// error function hangs flashing an LED
-void error();
 // set-up the on-board LEDs and switches
 void init_K64F();
-// SW2 interrupt service routine
-void sw2_isr();
+// Button A interrupt service routine
+void buttonA_isr();
 
 int main()
 {
     // initialise on-board LED and switches
     init_K64F();
     
-    // SW2 has a pull-up resistor, so the pin will be at 3.3 V by default
-    // and fall to 0 V when pressed. We therefore need to look for a falling edge
-    // on the pin to fire the interrupt
-    sw2.fall(&sw2_isr);
+    // Button A is connected between the pin and 3.3 V, we therefore need to turn on the internal pull-down resister
+    buttonA.mode(PullDown);
+    
+    // It will return 0 by default and a 1 when pressed i.e. cause a rising edge
+    buttonA.rise(&buttonA_isr);
     
     // set inital state
     int state = 0;
@@ -63,8 +64,8 @@
     while(1) {  // loop forever
     
         // check if flag i.e. interrupt has occured
-        if (g_sw2_flag) {
-            g_sw2_flag = 0;  // if it has, clear the flag
+        if (g_buttonA_flag) {
+            g_buttonA_flag = 0;  // if it has, clear the flag
 
             // swap direction when button has been pressed
             // (could just use ! but want this to be explicit to aid understanding)
@@ -121,12 +122,12 @@
                 }
                 break;
             default:  // default case
-                error();  //invalid state - call error routine
+                error("Invalid state!");  //invalid state - call error routine
                 // or could jump to starting state i.e. state = 0
                 break;
         }
 
-    wait(0.2); // small delay
+    wait(0.5); // small delay
 
 
     }
@@ -146,18 +147,8 @@
 
 }
 
-void error()
+// Button A event-triggered interrupt
+void buttonA_isr()
 {
-    while(1) {  // if error, hang while flashing error message
-        r_led = 0;
-        wait(0.2);
-        r_led = 1;
-        wait(0.2);
-    }
-}
-
-// SW2 event-triggered interrupt
-void sw2_isr()
-{
-    g_sw2_flag = 1;   // set flag in ISR
+    g_buttonA_flag = 1;   // set flag in ISR
 }
\ No newline at end of file