Revision 4:dc6e0fdcf6b4, committed 2018-02-15

Comitter:

Bossman

Date:

Thu Feb 15 17:19:16 2018 +0000

Parent:

3:1df612e3c838

Commit message:

Version 2

Changed in this revision

--- a/main.cpp	Fri Feb 09 21:13:03 2018 +0000
+++ /dev/null	Thu Jan 01 00:00:00 1970 +0000
@@ -1,37 +0,0 @@
-// Lab 3 Example Program 2
-// -----------------------
-// Periodically write to the AnalogOut to create a sine wave
-// Alternate between two fixed frequencies every 5 sec
-//
-// Updated for mbed 5
-
-// THIS VERSION HAS NO DEBUGGING CODE
-
-#include "mbed.h"
-#include "sineTable.h"
-
-Ticker tick ;          // Creates periodic interrupt
-AnalogOut ao(PTE30) ;  // Analog output
-
-
-// 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 ;   
-}
-
-// Control the frequency of updates
-//   Alternative between two frequencies      
-int main() {
-    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
-    }
-}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/name.cpp	Thu Feb 15 17:19:16 2018 +0000
@@ -0,0 +1,88 @@
+//   Revised for mbed 5
+
+#include "mbed.h"
+#include "sineTable.h"
+
+Ticker tickout ;          // Creates periodic interrupt
+AnalogOut ao(PTE30) ;  // Analog output
+
+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;
+
+// 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) ;
+}
+
+volatile int index = 0 ; // index into array of sin values
+void writeAout() {
+    ao.write_u16(sine[index]) ;
+    index = (index + 1) % 64 ;   
+}
+
+// Main program
+//   Initialise variables
+//   Attach ISR for ticker
+//   Procss messages from mailbox   
+int main() {
+    
+    int update_us = 1000 ;
+    int volts = 0;
+    led1 = 1 ; // turn off 
+   // 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);
+        }
+
+    }
+}
\ No newline at end of file