Diff: main.cpp

Revision:

1:0c3b6cc480b6

Parent:

0:1a3aa2e25db9

--- a/main.cpp	Fri Nov 04 22:07:07 2016 +0000
+++ b/main.cpp	Mon Feb 13 14:56:00 2017 +0000
@@ -1,7 +1,6 @@
 #include <mbed.h>
 
 #include "USBControl.h"
-//#include "TSISensor.h"
 
 #define VENDOR_ID 0x0004
 #define PRODUCT_ID 0x0307
@@ -23,44 +22,62 @@
     }
 };
 
-USBKnob usb;
-//TSISensor touch;
+
+//DigitalOut red(LED_RED);
+//DigitalOut green(LED_GREEN);
+//DigitalOut blue(LED_BLUE);
+
+AnalogIn knob(PTC2);
 
-DigitalOut red(LED_RED);
-DigitalOut green(LED_GREEN);
-DigitalOut blue(LED_BLUE);
-
-Serial pc(USBTX, USBRX);
-
-AnalogIn knob(A0);
+// ReadKnob reads the knob until the value is sufficiently
+// changed from the previousValue. The longer time goes on the
+// more the difference has to be (up to a point).
+//
+// Values are 16 bit.
+int ReadKnob(int previousValue)
+{
+    int centiseconds = 0;
+    
+    for (;;)
+    {
+        int val = knob.read_u16();
+        
+        int difference = abs(val - previousValue);
+        
+        // TODO: Check these.
+        if (centiseconds < 10 && difference > 100)
+            return val;
+        else if (difference > 1000)
+            return val;
+        
+        Thread::wait(10);
+        if (centiseconds < 1000)
+            ++centiseconds;
+    }
+}
 
 int main(int argc, char* argv[])
 {
-    pc.baud(115200);
-    pc.printf("\n\n\nmBed WinUSB Knob Example\n");
-    red = 1;
-    green = 1;
-    blue = 1;
+    // So, for some reason this doesn't work with mBed OS 5.
+    
+    USBKnob usb;
 
     usb.connect();
     
-    // Touch sensor example (for FRDM-KL25Z).
-//    for (;;)
-//    {
-//        float f = touch.readPercentage();
-//        if (f != 0.0)
-//        {
-//            // Note that this blocks if no-one is reading it!
-//            usb.send(0xFFFFFFFF * f);
-//            green = !green;
-//            wait_ms(10);
-//        }
-//    }
+    // We'll use a time-dependent threshold. Basically we take the time
+    // since we sent the last value, and then plug it into some kind of
+    // curve to give a threshold. Then we compare the current value to
+    // the previous value, and if the difference is greater than the threshold
+    // we send it.
+    
+    const int THRESHOLD = 0x0100; // 1/256
+
+    int val = knob.read_u16();
+    
     for (;;)
     {
-        // TODO: Only send when it changes.
-        usb.send(0xFFFFFFFF * knob);
-        wait_ms(100);
+        val = ReadKnob(val);
+        usb.send(static_cast<uint32_t>(val) << 16);
     }
     return 0;
 }
\ No newline at end of file