Diff: main.cpp

Revision:

3:f5d7fddeef39

Parent:

1:126dd2f5fc2d

Child:

4:ebd00f94455a

--- a/main.cpp	Wed Jan 23 17:05:06 2019 +0000
+++ b/main.cpp	Thu Jan 31 11:10:30 2019 +0000
@@ -1,6 +1,6 @@
 
 // LAB 3 SAMPLE PROGRAM 1
-//   Revised for mbed 5
+//   Revised for mbed 5 
 
 #include "mbed.h"
 
@@ -8,9 +8,13 @@
 Ticker tick;                // Ticker for reading analog
 AnalogIn ain(A0) ;          // Analog input
 DigitalOut led1(LED_RED);   // Red LED
+DigitalOut led2(LED_BLUE);   // BLUE LED
 
 Serial pc(USBTX, USBRX); // tx, rx, for debugging
 
+// Variable for a second thread
+Thread ADCthread;
+
 // Message type
 typedef struct {
   uint16_t analog; /* Analog input value */
@@ -22,19 +26,23 @@
 // Function called every 10ms to read ADC
 // Low pass filter  
 // Every 10th value is sent to mailbox
-volatile int samples = 0 ;
-volatile uint16_t smoothed = 0 ; 
 void readA0() {
-    smoothed = (smoothed >> 1) + (ain.read_u16() >> 1) ;
-    samples++ ;
-    if (samples == 10) {
-        // send to thread
-        message_t *mess = mailbox.alloc() ; // may fail but does not block
-        if (mess) {
-            mess->analog = smoothed ;
-            mailbox.put(mess); // fails but does not block if full
+    int samples = 0 ;
+    uint16_t smoothed = 0 ; 
+    while (true) {
+        wait(0.01) ; // every 10 ms
+        led2 = 1 ;
+        smoothed = (smoothed >> 1) + (ain.read_u16() >> 1) ;
+        samples++ ;
+        if (samples == 10) {
+            // send to thread
+            message_t *mess = mailbox.alloc() ; // may fail but does not block
+            if (mess) {
+                mess->analog = smoothed ;
+                mailbox.put(mess); // fails but does not block if full
+            }
+            samples = 0;
         }
-        samples = 0;
     }       
 }
 
@@ -58,8 +66,10 @@
     const int threshold = 100 ;
     int counter = 0 ;
     char vstring[] = "X.XX\r\n" ;
+    
+    // start the ADC reading thread
+    ADCthread.start(callback(readA0));
 
-    tick.attach_us(callback(&readA0), 10000); // ticks every 10ms
     while (true) {
         osEvent evt = mailbox.get(); // wait for mail 
         if (evt.status == osEventMail) {