Revision 3:30484e9b750a, committed 2018-02-15

Comitter:

Tobden

Date:

Thu Feb 15 17:30:18 2018 +0000

Parent:

2:e27fd3b65155

Commit message:

Modified version

Changed in this revision

--- a/main.cpp	Wed Jan 24 22:56:54 2018 +0000
+++ b/main.cpp	Thu Feb 15 17:30:18 2018 +0000
@@ -11,7 +11,49 @@
 #include "sineTable.h"
 
 Ticker tick ;          // Creates periodic interrupt
+Ticker tick2;           // Creates another periodic interrupt
 AnalogOut ao(PTE30) ;  // Analog output
+AnalogIn ain(A0) ;
+Serial pc(USBTX, USBRX); // tx, rx, for debugging
+//volatile int t;
+
+// Message type
+typedef struct {
+  uint16_t analog; /* Analog input value */
+} message_t;
+
+// Mail box
+Mail<message_t, 2> mailbox;
+
+// 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;
+    }       
+}
+
+// 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) ;
+}
+
 
 // Function called periodically
 // Write new value to AnalogOut 
@@ -24,13 +66,37 @@
 // Control the frequency of updates
 //   Alternative between two frequencies      
 int main() {
+    int volts = 0 ;
+    int counter = 0 ;
+    char vstring[] = "X.XX\r\n" ;
+
+    tick2.attach_us(callback(&readA0), 10000); // ticks every 10ms
     int update_us = 1000 ; // 1ms
     while (true) {
-        tick.attach_us(callback(&writeAout), update_us); // setup ticker to write to AnalogOut
-        Thread::wait(30000) ; // wait 30 sec - 30000ms
-        update_us = 2000 ; // 2ms
-        tick.attach_us(callback(&writeAout), update_us); // setup ticker to write to AnalogOut
-        Thread::wait(30000) ; // wait 30 sec - 30000ms
-        update_us = 1000 ; // 1ms
+         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
+
+         //t = 1000000/((1+(49*volts/330))*64);
+            //update_us = t;
+           update_us = 1000000/((1+(49*volts/330))*64);
+            tick.attach_us(callback(&writeAout), update_us); 
+           // if (volts > threshold) led1 = 0 ; else led1 = 1 ;
+            vToString(volts, vstring) ;
+            counter++ ;
+            if (counter == 10) {  // limit bandwidth of serial
+                pc.printf(vstring) ;
+               counter = 0 ;
+     }
+       }
+        // setup ticker to write to AnalogOut
+        //Thread::wait(30000) ; // wait 30 sec - 30000ms
+        // The varying update time for the ticker
+        
+        //tick.attach_us(callback(&writeAout), update_us); // setup ticker to write to AnalogOut
+      //  Thread::wait(30000) ; // wait 30 sec - 30000ms
+      //  update_us = 1000 ; // 1ms
     }
 }