Diff: main.cpp

Revision:

3:fcf87401c1b2

Parent:

2:b88c9b2c4c34

Child:

4:78ec71fcb981

--- a/main.cpp	Fri Feb 09 23:31:23 2018 +0000
+++ b/main.cpp	Wed Feb 14 15:43:28 2018 +0000
@@ -1,64 +1,101 @@
-// Lab 3 Example Program 2
-// -----------------------
-// Periodically write to the AnalogOut to create a sine wave
-// Alternate between two fixed frequencies every 5 sec
-//
-// THIS VERSION HAS DEBUGGING CODE USING THE SERIAL PORT
-
-// Revised for mbed 5
+//LAB 3 SAMPLE PROGRAM 2
+//   Revised for mbed 5
 
 #include "mbed.h"
 #include "sineTable.h"
 
-Ticker tick ;          // Creates periodic interrupt
+Ticker tickout ;          // Creates periodic interrupt
 AnalogOut ao(PTE30) ;  // Analog output
 
-// --- following code for debugging ---
-Thread debugT ;
-Serial pc(USBTX, USBRX); // tx, rx, useful for debugging
+Ticker tick;                // Ticker for reading analog
+AnalogIn ain(A0) ;          // Analog input
+DigitalOut led1(LED_RED);
+  
+
+Serial pc(USBTX, USBRX); // tx, rx, for debugging
+
+// Message type
+typedef struct {
+  uint16_t analog; /* Analog input value */
+} message_t;
+
+// Mail box
+Mail<message_t, 2> mailbox;
 
-// Put a simple reprsentation of the sine wave
-//  to the serial output. ONLY at low frequency
-void debug(int index) {
-    int sine4 = sine[index] >> 11 ; // get top 5 bits
-    pc.putc('*') ;
-    while (sine4--) pc.putc('*') ;
-    pc.putc('\n') ;
-    //pc.putc('\r') ;  
+// 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
+        }
+        samples = 0;
+    }       
 }
 
-
-volatile int index = 0 ; // this variable is not just for debugging!!
+// Write voltage digits
+//   v  Voltage as scale int, e.g. 3.30 is 330
+void vToString(int v, char* s) {    
+    s[3] = '0' + (v % 10) ;
+    v = v / 10 ;
+    s[2] = '0' + (v % 10) ;
+    v = v / 10 ;
+    s[0] = '0' + (v % 10) ;
+}
 
-void debugCallback() {
-    while (true) {
-        Thread::signal_wait(0x1) ;
-        debug(index) ;  // there is a race condition here
-    }
-}
-// ---- end of debugging code ---------
-
-// Function called every periodically
-// Write new value to AnalogOut 
+volatile int index = 0 ; // index into array of sin values
 void writeAout() {
     ao.write_u16(sine[index]) ;
-    debugT.signal_set(0x1) ; // DEBUGGING low frequency only
     index = (index + 1) % 64 ;   
 }
 
-// Control the frequency of updates
-//   Alternative between two frequencies      
+// Main program
+//   Initialise variables
+//   Attach ISR for ticker
+//   Procss messages from mailbox    
 int main() {
-    int update_us = 100000 ; // 100ms
-    debugT.start(&debugCallback) ;
-    while (true) {
-        pc.printf("Update at 64 x 100ms giving about 0.15Hz\n");
-        tick.attach_us(callback(&writeAout), update_us); // setup ticker to write to AnalogOut
-        Thread::wait(30000) ; // wait 30 sec - 30000ms
-        update_us = 150000 ; // 150ms
-        pc.printf("Update at 64 x 150ms giving about 0.1Hz\n");
-        tick.attach_us(callback(&writeAout), update_us); // setup ticker to write to AnalogOut
-        Thread::wait(30000) ; // wait 30 sec - 30000ms
-        update_us = 100000 ; // 100ms
+    
+    int update_us = 1000 ;
+    float tempupdate = 0.0;
+    int volts = 0;
+    led1 = 1 ; // turn off 
+    int counter = 0 ;
+    char vstring[] = "X.XX\r\n" ;
+ 
+    tick.attach_us(callback(&readA0), 10000); // ticks every 10ms
+   
+
+    while (true) 
+    {  
+        osEvent evt = mailbox.get(); // wait for mail 
+        if (evt.status == osEventMail) 
+        {
+            message_t* mess = (message_t*)evt.value.p ;
+            volts = (mess->analog * 330) / 0xffff ;
+            mailbox.free(mess) ;  // free the message space
+            
+           update_us = 1000000/((1+(49*volts/330))*64) ;
+           tickout.detach() ;
+           tickout.attach_us(callback(&writeAout), update_us);
+
+           // vToString(volts, vstring) ;
+          
+ /*           counter++ ;
+            if (counter == 10) {  // limit bandwidth of 
+                pc.printf(vstring);
+                pc.printf("%d\n",update_us);
+                counter = 0 ;
+            }
+            */
+        }
+
     }
-}
+}
\ No newline at end of file