Revision 6:a5841dd9e3b2, committed 2020-02-27

Comitter:

sebbarpar

Date:

Thu Feb 27 09:47:08 2020 +0000

Parent:

5:1f36332ed463

Commit message:

Lab 3;

Changed in this revision

diff -r 1f36332ed463 -r a5841dd9e3b2 main.cpp
--- a/main.cpp	Thu Feb 06 08:11:53 2020 +0000
+++ b/main.cpp	Thu Feb 27 09:47:08 2020 +0000
@@ -1,13 +1,34 @@
 
-// LAB 3 SAMPLE PROGRAM 1
-//   Revised for mbed 5 
-//   Revised to replace Ticker with event queue and thread
+// LAB 3 
+//After pressing the button, maximum voltage is set.
+//Divided by 5(5 LEDs) and each LED assigned a threshold.
+//LED is turned on when threshold is surpassed.
 
 #include "mbed.h"
+#include "sineTable.h"
 
+class AnalogOut_unsafe : public AnalogOut {
+  public:
+    AnalogOut_unsafe (PinName pin) : AnalogOut (pin) {} 
+  protected: 
+    virtual void lock() {}
+    virtual void unlock() {}
+};
+// --------------------------
+
+Ticker tick ;          // Creates periodic interrupt
+AnalogOut_unsafe ao(PTE30) ;  // Analog output
 
 AnalogIn ain(A0) ;          // Analog input
-DigitalOut led1(LED_RED);   // Red LED
+//Connected LEDs
+DigitalOut led1(PTE1);     
+DigitalOut led2(PTE0);
+DigitalOut led3(PTD7);
+DigitalOut led4(PTD6);
+DigitalOut led5(PTE31);
+//Button to set maximum voltage
+InterruptIn button(PTD5); //Button 1
+
 EventQueue queue;  // creates an event queue, to call read ADC
 
 Serial pc(USBTX, USBRX); // tx, rx, for debugging
@@ -28,6 +49,12 @@
 // Every 10th value is sent to mailbox
 volatile int samples = 0 ;
 volatile uint16_t smoothed = 0 ; 
+volatile int buttonEvent=0;
+
+//Interrupt to detect button switch
+void buttonCallback(){
+    buttonEvent=1;  
+}
 
 void readA0() {
     smoothed = (smoothed >> 1) + (ain.read_u16() >> 1) ;
@@ -53,36 +80,78 @@
     s[0] = '0' + (v % 10) ;
 }
 
+
+
+
+// Function called periodically
+// Write new value to AnalogOut 
+volatile int index = 0 ; // index into array of sin values
+void writeAout() {
+    ao.write_u16(sine[index]) ;
+    index = (index + 1) % 64 ;   
+}
+
+volatile int t=312;
+volatile int freq=1;
+
 // Main program
 //   Initialise variables
 //   Attach ISR for ticker
 //   Procss messages from mailbox    
 int main() {
-    led1 = 1 ; // turn off 
+    led1=0 ; // turn off 
+    led2=0;
+    led3=0;
+    led4=0;
+    led5=0;
     int volts = 0 ;
-    const int threshold = 100 ;
+    int i=0;
+    int threshold[5]={400,400,400,400,400};
     int counter = 0 ;
     char vstring[] = "X.XX\r\n" ;
+    char max[] = "X.XX\r\n" ;//For debugging
+    int maxvalue=1;
+    button.fall(&buttonCallback) ; 
     
     // Start the event queue
     eventThread.start(callback(&queue, &EventQueue::dispatch_forever));
-
     // call the readA0 function every 10ms 
     queue.call_every(10, readA0) ; 
-
+    
     while (true) {
         osEvent evt = mailbox.get(); // wait for mail 
+        tick.attach_us(callback(&writeAout), t); // setup ticker to write to AnalogOut
+        //pc.printf("%d",t); //For debugging
         if (evt.status == osEventMail) {
             message_t* mess = (message_t*)evt.value.p ;
+             if (buttonEvent==1){//When button is pressed establish maximum value and thresholds
+                buttonEvent=0;
+                maxvalue=(mess->analog * 330) / 0xffff;
+                for (i=1;i<=5;i++){
+                    threshold[i-1]=maxvalue*i/5;//Set values for thresholds
+                }
+            }
             volts = (mess->analog * 330) / 0xffff ;
+            //Calculate frequency to call the function to write the DAC
+            freq=1+(49*volts/maxvalue);
+            if (freq>50) freq=50;
+            t=(1000000/(freq*64));
             mailbox.free(mess) ;  // free the message space
-            if (volts > threshold) led1 = 0 ; else led1 = 1 ;
+            //Turn on LEDs depending on the range of voltage
+            if (volts < threshold[0]) led1 = 0 ; else led1 = 1 ;
+            if (volts < threshold[1]) led2 = 0 ; else led2 = 1 ;
+            if (volts < threshold[2]) led3 = 0 ; else led3 = 1 ;
+            if (volts < threshold[3]) led4 = 0 ; else led4 = 1 ;
+            if (volts < threshold[4]) led5 = 0 ; else led5 = 1 ;
             vToString(volts, vstring) ;
+            vToString(maxvalue, max) ;
             counter++ ;
-            if (counter == 10) {  // limit bandwidth of serial
-                pc.printf(vstring) ;
+            /*if (counter == 10) {  // limit bandwidth of serial
+                //pc.printf(vstring) ;
+                pc.printf("%d \n",freq);
+                pc.printf("%d \n",t);
                 counter = 0 ;
-            }
+            }*/ //For debugging
         }
     }
 }

diff -r 1f36332ed463 -r a5841dd9e3b2 sineTable.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/sineTable.h	Thu Feb 27 09:47:08 2020 +0000
@@ -0,0 +1,15 @@
+// Look up table for a sine wave as 16 bits
+// Note that it is possible to construct the full period from 
+//   the first quarter, but the code is more complex
+//
+// These number were calcuated using a spreadsheet 
+const uint16_t sine[] = {
+    32768, 35980, 39161, 42280, 45308, 48215, 50973, 53556, 
+    55938, 58098, 60014, 61667, 63042, 64125, 64906, 65378, 
+    65535, 65378, 64906, 64125, 63042, 61667, 60014, 58098,
+    55938, 53556, 50973, 48215, 45308, 42280, 39161, 35980,
+    32768, 29556, 26375, 23256, 20228, 17321, 14563, 11980,
+     9598,  7438,  5522,  3869,  2494,  1411,   630,   158, 
+        0,   158,   630,  1411,  2494,  3869,  5522,  7438,
+     9598, 11980, 14563, 17321, 20228, 23256, 26375, 29556
+    } ;
\ No newline at end of file