initial cleanup and mapping

examples/Gertboard/gertboard.c

@@ -0,0 +1,96 @@
+/*
+ * gertboard.c:
+ *	Simple test for the SPI bus on the Gertboard
+ *
+ *	Hardware setup:
+ *		D/A port 0 jumpered to A/D port 0.
+ *
+ *	We output a sine wave on D/A port 0 and sample A/D port 0. We then
+ *	plot the input value on the terminal as a sort of vertical scrolling
+ *	oscilloscipe.
+ *
+ * Copyright (c) 2012-2013 Gordon Henderson. <projects@drogon.net>
+ ***********************************************************************
+ * This file is part of wiringPi:
+ *	https://projects.drogon.net/raspberry-pi/wiringpi/
+ *
+ *    wiringPi is free software: you can redistribute it and/or modify
+ *    it under the terms of the GNU Lesser General Public License as published by
+ *    the Free Software Foundation, either version 3 of the License, or
+ *    (at your option) any later version.
+ *
+ *    wiringPi is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU Lesser General Public License for more details.
+ *
+ *    You should have received a copy of the GNU Lesser General Public License
+ *    along with wiringPi.  If not, see <http://www.gnu.org/licenses/>.
+ ***********************************************************************
+ */
+
+#include <stdio.h>
+#include <sys/ioctl.h>
+#include <stdlib.h>
+#include <math.h>
+
+// Gertboard D to A is an 8-bit unit.
+
+#define	B_SIZE	256
+
+#include <wiringPi.h>
+#include <gertboard.h>
+
+int main (void)
+{
+  double angle ;
+  int i, inputValue ;
+  int  buffer [B_SIZE] ;
+  int   cols ;
+  struct winsize w ;
+
+
+  printf ("Raspberry Pi Gertboard SPI test program\n") ;
+  printf ("=======================================\n") ;
+
+  ioctl (fileno (stdin), TIOCGWINSZ, &w);
+  cols = w.ws_col - 2 ;
+
+// Always initialise wiringPi. Use wiringPiSys() if you don't need
+//	(or want) to run as root
+
+  wiringPiSetupSys () ;
+
+// Initialise the Gertboard analog hardware at pin 100
+
+  gertboardAnalogSetup (100) ;
+
+// Generate a Sine Wave and store in our buffer
+
+  for (i = 0 ; i < B_SIZE ; ++i)
+  {
+    angle = ((double)i / (double)B_SIZE) * M_PI * 2.0 ;
+    buffer [i] = (int)rint ((sin (angle)) * 127.0 + 128.0) ;
+  }
+
+// Loop, output the sine wave on analog out port 0, read it into A-D port 0
+//	and display it on the screen
+
+  for (;;)
+  {
+    for (i = 0 ; i < B_SIZE ; ++i)
+    {
+      analogWrite (100, buffer [i]) ;
+
+      inputValue = analogRead (100) ;
+
+// We don't need to wory about the scale or sign - the analog hardware is
+//	a 10-bit value, so 0-1023. Just scale this to our terminal
+
+      printf ("%*s\n", (inputValue * cols) / 1023, "*") ;
+      delay (2) ;
+    }
+  }
+
+  return 0 ;
+}