Adds tests for the new QDEC Peripheral in tockOS

examples/tests/qdec_callback/Makefile

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+# Makefile for user application
+
+# Specify this directory relative to the current application.
+TOCK_USERLAND_BASE_DIR = ../../..
+
+# Which files to compile.
+C_SRCS := $(wildcard *.c)
+
+# Include userland master makefile. Contains rules and flags for actually
+# building the application.
+include $(TOCK_USERLAND_BASE_DIR)/AppMakefile.mk

examples/tests/qdec_callback/README.md

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+QDEC Callback Test
+
+This test's purposed is to ensure the interrupts work
+as expected and the callbacks work as expected every 
+time the QDEC is rotated.
+
+To verify the test is working properly, fire up the QDEC 
+timer program, and without touching the encoder, you should 
+see the following initial statements (If anything else is printed, 
+that is a signal that there was an error when setting up the QDEC):
+
+'Starting The [QDEC] Test App for Callbacks
+QDEC has been fully initiated!'
+
+Then, turning the QDEC in the positive direction
+one click will invoke the callback method and a new statment will
+be printed: 
+
+QDEC Absolute Position: 1
+QDEC Absolute Position: 2
+QDEC Absolute Position: 3
+QDEC Absolute Position: 4
+
+Similarly, turning the QDEC in the negative direction (from the initial 
+starting location) one click will invoke the callback method and a new 
+statment will be printed: 
+
+QDEC Absolute Position: -1
+QDEC Absolute Position: -2
+QDEC Absolute Position: -3
+QDEC Absolute Position: -4
+
+These are good initial tests to ensure the QDEC is working as expected.
+Continue the QDEC in both directions and see if the progression of values 
+displayed on the screen are logical.

examples/tests/qdec_callback/main.c

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+#include <led.h>
+#include <qdec.h>
+#include <timer.h>
+#include <tock.h>
+
+static void qdec_callback(int qdec_num,
+                          __attribute__ ((unused)) int val,
+                          __attribute__ ((unused)) int arg2,
+                          __attribute__ ((unused)) void *ud) {
+  printf("QDEC Absolute Position: %d\n", qdec_num);
+}
+
+int main(void) {
+  printf("Starting The [QDEC] Test App for Callbacks\n");
+  if (!qdec_exists()) {
+    printf("No QDEC driver\n");
+    return -1;
+  }
+  qdec_enable();
+  if (qdec_subscribe(qdec_callback, NULL) != 0) {
+    printf("Can't subscribe  to interrupt results!");
+    return -1;
+  }
+  if (!qdec_interrupt_enable()) {
+    printf("Can't enable interrupts!\n");
+    return -1;
+  }
+  printf("QDEC has been fully initiated!\n");
+  return 0;
+}

examples/tests/qdec_timer/Makefile

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+# Makefile for user application
+
+# Specify this directory relative to the current application.
+TOCK_USERLAND_BASE_DIR = ../../..
+
+# Which files to compile.
+C_SRCS := $(wildcard *.c)
+
+# Include userland master makefile. Contains rules and flags for actually
+# building the application.
+include $(TOCK_USERLAND_BASE_DIR)/AppMakefile.mk

examples/tests/qdec_timer/README.md

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+QDEC Timer Test
+
+This test's purposed is to ensure the interrupts work
+as expected and the approximately correct displacement
+is being returned with each fire of the timer.
+
+To verify the test is working properly, fire up the QDEC 
+timer program, and without touching the encoder, you should 
+see the statement 'Displacement val: 0' print on the screen
+every 500 seconds. Turning the QDEC in the positive direction
+one click will change the print statement to 'Displacement 
+val: 4' for one timer fired instance and then return back to
+'Displacement val: 0'. Similarly, turning it in the negative 
+direction one click will change the print statement to 
+'Displacement val: -4' for one timer fired instance and then 
+return back to 'Displacement val: 0'.

examples/tests/qdec_timer/main.c

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+#include <led.h>
+#include <qdec.h>
+#include <timer.h>
+#include <tock.h>
+
+static void timer_fired ( __attribute__ ((unused)) int arg0,
+                          __attribute__ ((unused)) int arg1,
+                          __attribute__ ((unused)) int arg2,
+                          __attribute__ ((unused)) void *ud) {
+  int qdec_num = qdec_displacement();
+  printf("Displacement val: %d\n", qdec_num);
+}
+
+int main(void) {
+  printf("Starting The [QDEC] Test App for Timers\n");
+  if (!qdec_exists()) {
+    printf("No QDEC driver\n");
+    return -1;
+  }
+  qdec_enable();
+  if (!qdec_interrupt_enable()) {
+    printf("Can't enable interrupts!\n");
+    return -1;
+  }
+  printf("QDEC has been fully initiated!\n");
+  static tock_timer_t timer;
+  timer_every(500, timer_fired, NULL, &timer);
+  printf("Timer set!\n");
+  return 0;
+}

libtock/qdec.c

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+#include "qdec.h"
+
+bool qdec_exists(void) {
+  return command(DRIVER_NUM_QDEC, 0, 0, 0) >= 0;
+}
+
+bool qdec_enable(void) {
+  return command(DRIVER_NUM_QDEC, 1, 0, 0) >= 0;
+}
+
+bool qdec_disable(void) {
+  return command(DRIVER_NUM_QDEC, 2, 0, 0) >= 0;
+}
+
+bool qdec_interrupt_enable(void) {
+  return command(DRIVER_NUM_QDEC, 3, 0, 0) >= 0;
+}
+
+int qdec_subscribe(subscribe_cb callback, void* callback_args) {
+  return subscribe(DRIVER_NUM_QDEC, 0, callback, callback_args);
+}
+
+int qdec_displacement(void) {
+  return command(DRIVER_NUM_QDEC, 4, 0, 0);
+}

libtock/qdec.h

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+/**
+ * Quadrature Decoder (QDEC)
+ *
+ * A QDEC provides buffered decoding of quadrature-encoded signals. It is suitable
+ * for mechanical and optical sensors.
+ *
+ * Use for the QDEC would be hooking up a rotary encoder or other optical encoder to
+ * the respective ports and using the below series of function to decode the signals
+ * sent by the encoders and turn them into useful metrics (i.e. displacement)
+ *
+ */
+#pragma once
+
+#include "tock.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define DRIVER_NUM_QDEC 0x90003
+
+/*Verifies the existence of the QDEC*/
+bool qdec_exists(void);
+/*Enables the QDEC*/
+bool qdec_enable(void);
+/*Disables the QDEC*/
+bool qdec_disable(void);
+/*Enables QDEC interrupts needed to get displacement values*/
+bool qdec_interrupt_enable(void);
+/*Subscribes the app to QDEC interrupt calls*/
+int qdec_subscribe(subscribe_cb callback, void* callback_args);
+/*Gets the displacement of the QDEC from its last stopped position*/
+int qdec_displacement(void);
+
+#ifdef __cplusplus
+}
+#endif