Diff: LaserMon-ScanInput.cpp

Revision:

1:b9d4b9b8884c

Parent:

0:1ebe7d222470

Child:

2:cbcf2695a4a1

--- a/LaserMon-ScanInput.cpp	Mon Jun 10 17:10:01 2019 +0000
+++ b/LaserMon-ScanInput.cpp	Fri Jun 14 21:11:31 2019 +0000
@@ -26,10 +26,7 @@
 
     // We create an analog input
     static AnalogIn st_scanInput(LASER_SCAN_IN);
-    
-    // We will be creating a thread
-    static Thread st_scanInputThread;
-    
+
     // For diagnostic purposes to show that the Laser Scan is operating
     static DigitalOut st_scanInputLED(LED2);
     
@@ -40,10 +37,17 @@
     // This value contains the next scan line number to plot
     static uint16_t u16_nextScanLine;
     
+    // We store the last pixel's height so we may plot
     static uint16_t u16_lastHeight = 0;
     
-    bool b_done = false;
+    // Flag indicates whether we believe we are receiving porch or not
+    static bool b_inPorch;
     
+    static uint16_t u16_resyncCount;
+    static uint32_t u32_scanCount;
+    
+    static bool b_waitingForPorch;
+   
 // ----------------------------------------------------------------------
 // ScanInputPlotThisValue()
 //
@@ -65,30 +69,78 @@
 static void ScanInputPlotThisValue(float f_analogValue)
 {
     // Compute the percentage of LCD height
-    uint16_t u16_pixelHeight = ((f_analogValue / 3.8f) * LCD_HEIGHT);
+    uint16_t u16_pixelHeight = ((f_analogValue / 3.3f) * ((float)LCD_HEIGHT - 10.0f));
     
     u16_pixelHeight /= 2;
     u16_pixelHeight += 10;
     
-    // Plot the pixel
-    if (u16_nextScanLine > 0)
+    // Clear the entire current scan line to plot
+    st_lcd.SetTextColor(LCD_COLOR_WHITE);
+    st_lcd.DrawLine(1, u16_nextScanLine, LCD_WIDTH, u16_nextScanLine);
+        
+    // Plot from the previous pixel to the new one
+    st_lcd.SetTextColor(LCD_COLOR_BLUE);
+    
+    // Are we currently in porch? We plot differently if so
+    if (false == b_inPorch)
     {
-        st_lcd.DrawLine(u16_pixelHeight, u16_nextScanLine, u16_lastHeight, u16_nextScanLine - 1);
+        // We plot ramp from the previous scan line's height to the current scan line and height
+        st_lcd.DrawLine(u16_lastHeight, u16_nextScanLine - 1, u16_pixelHeight, u16_nextScanLine);
     }
     else
     {
-        st_lcd.DrawPixel(u16_pixelHeight, u16_nextScanLine, LCD_COLOR_BLACK);
+        // We plot the porch at a height of 10 pixels
+        st_lcd.DrawLine(10, u16_nextScanLine - 1, 10, u16_nextScanLine);
     }
-    
+
+    // Keep track of the last height so we may plot
     u16_lastHeight = u16_pixelHeight;
+}
+
+// ----------------------------------------------------------------------
+//
+//
+// ----------------------------------------------------------------------
+static float ScanInputGetInputVoltage(void)
+{
+    // Get the current analog input value and convert to volts
+    float f_analogValue = st_scanInput.read() * 3.3f;
     
-    // Increment the scan line and see if it wrapped
-    if (++u16_nextScanLine >= LCD_WIDTH)
+#if WANT_TEST_SIGNAL
+    // Use the test output signal voltage instead
+    f_analogValue = f_rampVoltage;
+#endif
+
+    // Return either the actual analog in or test voltage 
+    return f_analogValue;
+}
+
+// ----------------------------------------------------------------------
+// ScanInputWaitForPorch()
+//
+// ----------------------------------------------------------------------
+static void ScanInputWaitForPorch(void)
+{
+    float f_analogValue = 5.0f;
+
+    // While we're not seeing porch, loop
+    if (f_analogValue > 0.5f)
     {
-        u16_nextScanLine = 40;
+        return;
+    }
         
-        b_done = true;
-    }
+    // Flag the fact that we're in porch
+    b_inPorch = true;
+    
+    b_waitingForPorch = false;
+    
+    // Since we detected porch, start the plot over from the beginning
+    u16_nextScanLine = 50;
+    
+    // The last height we consider to be 1 pixel on porch
+    u16_lastHeight = 1;
+    
+    ++u16_resyncCount;
 }
 
 // ----------------------------------------------------------------------
@@ -98,16 +150,50 @@
 // ----------------------------------------------------------------------
 static void ScanInputGetNextValue(void)
 {
-    // Get the current analog input value and convert to volts
-    float f_analogValue = st_scanInput.read() * 3.3f;
+    float f_analogValue = ScanInputGetInputVoltage();
 
-#if WANT_TEST_SIGNAL
-    // Use the test output signal voltage instead
-    f_analogValue = f_rampVoltage;
-#endif
+    // Dows the input indicate that we are in porch?
+    if (f_analogValue < 1.0f)
+    {
+        // Did we previously know that we were in porch?
+        if (false == b_inPorch)
+        {
+            char pch_testMessage[21] = { 0 };
+            
+            // Flag the fact that we're in porch now
+            b_inPorch = true;
+    
+            // Since we detected a new porch, start the plot over
+            u16_nextScanLine = 49;
+            
+            // The last height we consider to be 1 pixel on porch
+            u16_lastHeight = 1;
+            
+            (void)sprintf(pch_testMessage, "Resync %u, Scans %u", u16_resyncCount, ++u32_scanCount);
+            st_lcd.DisplayStringAt(1, LINE(0), (uint8_t *)pch_testMessage, LEFT_MODE);
+        }
+    }
+    else
+    {
+        // We are in the ramp so flag the fact even if we already know
+        b_inPorch = false;
+    }
 
+    // Indicate the next line to plot this reading on to
+    u16_nextScanLine++;
+    
     // Call the function which plots this value
-    ScanInputPlotThisValue(f_analogValue);
+    (void)ScanInputPlotThisValue(f_analogValue);
+    
+    // Are we about to exceed the display?
+    if (u16_nextScanLine >= (LCD_HEIGHT - 10))
+    {
+        // We have lost track of porch so we must search for it again
+        b_waitingForPorch = true;
+    }
+    
+    // Set the LED with whether we are at porch or not
+    st_scanInputLED = b_inPorch;
 }
     
 // ----------------------------------------------------------------------
@@ -119,20 +205,15 @@
 // development use.
 //
 // ----------------------------------------------------------------------
-static void ScanInputThread(void)
+void ScanInputThread(void)
 {
-    // This thread goes in to a forever loop waking up once a millisecond
-    while(true)
+    if (true == b_waitingForPorch)
     {
-        if (false == b_done)
-        {
-            // Drive the input scanner
-            ScanInputGetNextValue();
-        }
-        
-        // Wait for 1 millisecond
-        accurate_wait_ms(1);
+        // Start out searching for porch
+        ScanInputWaitForPorch();
     }
+
+    ScanInputGetNextValue();
 }
 
 // ----------------------------------------------------------------------
@@ -145,10 +226,14 @@
     st_scanInputLED = 1;
     
     // Initialize locally-held variables
-    u16_nextScanLine = 40;
+    u16_nextScanLine = 50;
     
-    // Launch the thread
-    st_scanInputThread.start(ScanInputThread);
+    // Flag the fact that we don't believe that we are seeing porch
+    b_inPorch         = false;
+    b_waitingForPorch = true;
+    
+    u16_resyncCount = 0;
+    u32_scanCount   = 0;
 }
 
 // End of file