feat:encoder with existing lib (#2)

Co-authored-by: Clement <c.boesmier@aptatio.com>
Reviewed-on: #2

lib/Encoder/examples/SpeedTest/SpeedTest.pde

@@ -0,0 +1,113 @@
+/* Encoder Library - SpeedTest - for measuring maximum Encoder speed
+ * http://www.pjrc.com/teensy/td_libs_Encoder.html
+ *
+ * This example code is in the public domain.
+ */
+
+
+// This SpeedTest example provides a simple way to verify how much
+// CPU time Encoder is consuming.  Connect a DC voltmeter to the
+// output pin and measure the voltage while the encoder is stopped
+// or running at a very slow speed.  Even though the pin is rapidly
+// pulsing, a DC voltmeter will show the average voltage.  Due to
+// software timing, it will read a number much less than a steady
+// logic high, but this number will give you a baseline reading
+// for output with minimal interrupt overhead.  Then increase the
+// encoder speed.  The voltage will decrease as the processor spends
+// more time in Encoder's interrupt routines counting the pulses
+// and less time pulsing the output pin.  When the voltage is
+// close to zero and will not decrease any farther, you have reached
+// the absolute speed limit.  Or, if using a mechanical system where
+// you reach a speed limit imposed by your motors or other hardware,
+// the amount this voltage has decreased, compared to the baseline,
+// should give you a good approximation of the portion of available
+// CPU time Encoder is consuming at your maximum speed.
+
+// Encoder requires low latency interrupt response.  Available CPU
+// time does NOT necessarily prove or guarantee correct performance.
+// If another library, like NewSoftSerial, is disabling interrupts
+// for lengthy periods of time, Encoder can be prevented from
+// properly counting the intput signals while interrupt are disabled.
+
+
+// This optional setting causes Encoder to use more optimized code,
+// but the downside is a conflict if any other part of your sketch
+// or any other library you're using requires attachInterrupt().
+// It must be defined before Encoder.h is included.
+//#define ENCODER_OPTIMIZE_INTERRUPTS
+
+#include <Encoder.h>
+#include "pins_arduino.h"
+
+// Change these two numbers to the pins connected to your encoder
+// or shift register circuit which emulates a quadrature encoder
+//  case 1: both pins are interrupts
+//  case 2: only first pin used as interrupt
+Encoder myEnc(5, 6);
+
+// Connect a DC voltmeter to this pin.
+const int outputPin = 12;
+
+/* This simple circuit, using a Dual Flip-Flop chip, can emulate
+   quadrature encoder signals.  The clock can come from a fancy
+   function generator or a cheap 555 timer chip.  The clock
+   frequency can be measured with another board running FreqCount
+   http://www.pjrc.com/teensy/td_libs_FreqCount.html
+
+                        +5V
+                         |        Quadrature Encoder Signal Emulator
+ Clock                   |
+ Input o----*--------------------------      ---------------------------o Output1
+            |            |14           |    |
+            |     _______|_______      |    |     _______________ 
+            |    |    CD4013     |     |    |    |    CD4013     |
+            |  5 |               | 1   |    |  9 |               | 13
+        ---------|  D         Q  |-----|----*----|  D         Q  |------o Output2
+       |    |    |               |     |         |               |
+       |    |  3 |               |     |      11 |               |
+       |     ----|> Clk          |      ---------|> Clk          |
+       |         |               |               |               |
+       |       6 |               |             8 |               |
+       |     ----|  S            |           ----|  S            |
+       |    |    |               |          |    |               |
+       |    |  4 |            _  | 2        | 10 |            _  | 12
+       |    *----|  R         Q  |---       *----|  R         Q  |----
+       |    |    |               |          |    |               |    |
+       |    |    |_______________|          |    |_______________|    |
+       |    |            |                  |                         |
+       |    |            | 7                |                         |
+       |    |            |                  |                         |
+        --------------------------------------------------------------
+            |            |                  |
+            |            |                  |
+          -----        -----              -----
+           ---          ---                ---
+            -            -                  -
+*/
+
+
+void setup() {
+  pinMode(outputPin, OUTPUT);
+}
+
+#if defined(__AVR__) || defined(TEENSYDUINO)
+#define REGTYPE unsigned char
+#else
+#define REGTYPE unsigned long
+#endif
+
+void loop() {
+  volatile int count = 0;
+  volatile REGTYPE *reg = portOutputRegister(digitalPinToPort(outputPin));
+  REGTYPE mask = digitalPinToBitMask(outputPin);
+
+  while (1) {
+    myEnc.read();	// Read the encoder while interrupts are enabled.
+    noInterrupts();
+    *reg |= mask;	// Pulse the pin high, while interrupts are disabled.
+    count = count + 1;
+    *reg &= ~mask;
+    interrupts();
+  }
+}
+