Diff: LaserMon-ScanInput.cpp

Revision:

0:1ebe7d222470

Child:

1:b9d4b9b8884c

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/LaserMon-ScanInput.cpp	Mon Jun 10 17:10:01 2019 +0000
@@ -0,0 +1,155 @@
+
+// ----------------------------------------------------------------------
+// LaserMon-ScanInput.cpp
+//
+// Fredric L. Rice, June 2019
+//
+// ----------------------------------------------------------------------
+
+#include "mbed.h"                   // The mbed operating system
+#include "LCD_DISCO_F429ZI.h"       // For controlling the LCD
+#include "TS_DISCO_F429ZI.h"        // For controlling the touch screen
+#include "LaserMon-Main.h"          // For data exported to us
+#include "LaserMon-TestOutput.h"    // For test signal
+
+// ----------------------------------------------------------------------
+// Options, defined constants, and MACROs
+//
+// ----------------------------------------------------------------------
+
+#define WANT_TEST_SIGNAL        1
+
+// ----------------------------------------------------------------------
+// Local data storage
+//
+// ----------------------------------------------------------------------
+
+    // 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);
+    
+    // There are LCD_HEIGHT possible scan lines with a height of
+    // LCD_WIDTH -- yes, the defined constant names are swapped
+    // because we plot sideways.
+    //
+    // This value contains the next scan line number to plot
+    static uint16_t u16_nextScanLine;
+    
+    static uint16_t u16_lastHeight = 0;
+    
+    bool b_done = false;
+    
+// ----------------------------------------------------------------------
+// ScanInputPlotThisValue()
+//
+// What percentage of LCD_HEIGHT is the voltage? We need to scale 0 to 
+// 3.3 volts across LCD_HEIGHT, with 0 being zero, and 3.3 volts being 
+// LCD_HEIGHT.
+//
+// We compute the percentage of 3.3 volts that the input signal is 
+// currently showing, then we compute that percentage of LCD_HEIGHT to
+// determine how many pixels on a scan line that percentage is. That
+// gives us the height of the plot line while u16_nextScanLine gives 
+// us the line to plot it on.
+//
+// This is easy because the value passed to this function is a value
+// from 0.0 to 1.0 which is a percentage of 3.3 volts, so we use the
+// value against LCD_HEIGHT to yield the percentage of height.
+//
+// ----------------------------------------------------------------------
+static void ScanInputPlotThisValue(float f_analogValue)
+{
+    // Compute the percentage of LCD height
+    uint16_t u16_pixelHeight = ((f_analogValue / 3.8f) * LCD_HEIGHT);
+    
+    u16_pixelHeight /= 2;
+    u16_pixelHeight += 10;
+    
+    // Plot the pixel
+    if (u16_nextScanLine > 0)
+    {
+        st_lcd.DrawLine(u16_pixelHeight, u16_nextScanLine, u16_lastHeight, u16_nextScanLine - 1);
+    }
+    else
+    {
+        st_lcd.DrawPixel(u16_pixelHeight, u16_nextScanLine, LCD_COLOR_BLACK);
+    }
+    
+    u16_lastHeight = u16_pixelHeight;
+    
+    // Increment the scan line and see if it wrapped
+    if (++u16_nextScanLine >= LCD_WIDTH)
+    {
+        u16_nextScanLine = 40;
+        
+        b_done = true;
+    }
+}
+
+// ----------------------------------------------------------------------
+// ScanInputGetNextValue()
+//
+//
+// ----------------------------------------------------------------------
+static void ScanInputGetNextValue(void)
+{
+    // Get the current analog input value and convert to volts
+    float f_analogValue = st_scanInput.read() * 3.3f;
+
+#if WANT_TEST_SIGNAL
+    // Use the test output signal voltage instead
+    f_analogValue = f_rampVoltage;
+#endif
+
+    // Call the function which plots this value
+    ScanInputPlotThisValue(f_analogValue);
+}
+    
+// ----------------------------------------------------------------------
+// ScanInputThread()
+//
+// This thread wakes up every 1 millisecond to drive the input of the
+// signal coming in on the analog input -- or if it's enabled, to drive
+// the input based on the test signal for diagnostic and software
+// development use.
+//
+// ----------------------------------------------------------------------
+static void ScanInputThread(void)
+{
+    // This thread goes in to a forever loop waking up once a millisecond
+    while(true)
+    {
+        if (false == b_done)
+        {
+            // Drive the input scanner
+            ScanInputGetNextValue();
+        }
+        
+        // Wait for 1 millisecond
+        accurate_wait_ms(1);
+    }
+}
+
+// ----------------------------------------------------------------------
+// ScanInputInit()
+//
+// ----------------------------------------------------------------------
+void ScanInputInit(void)
+{
+    // Start out with the LED turned ON
+    st_scanInputLED = 1;
+    
+    // Initialize locally-held variables
+    u16_nextScanLine = 40;
+    
+    // Launch the thread
+    st_scanInputThread.start(ScanInputThread);
+}
+
+// End of file
+