Merge pull request #7 from awonak/pin-change-interrupts

Add pin change interrupt handlers for A-RYTH-MATIK CLK & RST inputs.

Author: awonak

README.md

@@ -45,7 +45,8 @@ using namespace arythmatik;
 // Declare A-RYTH-MATIK hardware variable.
 Arythmatik hw;
 
-byte counter = 0;
+// Since counter is modified in the CLK/RST handler, it should be volatile.
+volatile int counter;
 
 void setup() {
     // Inside the setup, set config values prior to calling hw.Init().
@@ -60,6 +61,10 @@ void setup() {
     hw.eb.setEncoderHandler(UpdateRotate);
     hw.eb.setClickHandler(UpdatePress);
 
+    // Attach CLK & RST pin change handlers.
+    hw.AttachClockHandler(HandleClockPinChange);
+    hw.AttachResetHandler(HandleResetPinChange);
+
     // Initialize the A-RYTH-MATIK peripherials.
     hw.Init();
 }
@@ -68,11 +73,6 @@ void loop() {
     // Read cv inputs and process encoder state to determine state for this loop.
     hw.ProcessInputs();
 
-    // Advance the counter on CLK input
-    if (hw.clk.State() == DigitalInput::STATE_RISING) {
-        counter = ++counter % OUTPUT_COUNT;
-    }
-
     // Activate the current counter output.
     for (int i = 0; i < OUTPUT_COUNT; i++) {
         (i == counter)
@@ -87,6 +87,19 @@ void loop() {
     hw.display.display();
 }
 
+void HandleClockPinChange() {
+    // Advance the counter on CLK input
+    if (hw.clk.Read() == HIGH) {
+        counter = ++counter % OUTPUT_COUNT;
+    }
+}
+
+void HandleResetPinChange() {
+    if (hw.rst.Read() == HIGH) {
+        counter = 0;
+    }
+}
+
 void UpdateRotate(EncoderButton &eb) {
     // Read the configured encoder direction (according to hw.config.ReverseEncoder setting).
     Direction dir = hw.EncoderDirection();

analog_output.h

@@ -46,7 +46,7 @@ class AnalogOutput {
     /**
      * @brief Set the output pin to the given 8 bit value.
      *
-     * @param val Arduino analog value between 0 and 255 (0..5v).
+     * @param val Arduino analog value between 0 and 255 (0..10v).
      */
     inline void Update(int val) {
         update((val <= MAX_OUTPUT) ? val : MAX_OUTPUT);
@@ -55,22 +55,22 @@ class AnalogOutput {
     /**
      * @brief Set the output pin to the given 10 bit value.
      *
-     * @param val Arduino analog value between 0 and 1024 (0..5v).
+     * @param val Arduino analog value between 0 and 1024 (0..10v).
      */
     inline void Update10bit(int val) {
         val = val <= MAX_OUTPUT_10BIT ? val : MAX_OUTPUT_10BIT;
         val = map(val, 0, MAX_OUTPUT_10BIT, 0, MAX_OUTPUT);
         update(val);
     }
 
-    /// @brief Sets the cv output HIGH to about 5v.
+    /// @brief Sets the cv output HIGH to about 10v.
     inline void High() { update(MAX_OUTPUT); }
 
     /// @brief Sets the cv output LOW to 0v.
     inline void Low() { update(0); }
 
     /**
-     * @brief Return an integer value between 0 and 1023 (0..5v) representing the current value of the output.
+     * @brief Return an integer value between 0 and 1023 (0..10v) representing the current value of the output.
      *
      * @return integer value of cv from 0 to 1023.
      */

arythmatik.cpp

@@ -14,6 +14,11 @@
 using namespace modulove;
 using namespace arythmatik;
 
+static void (*ClockHandler)(void);
+static void (*ResetHandler)(void);
+void noop() {};
+
+
 void Arythmatik::Init() {
     InitInputs();
     InitOutputs();
@@ -45,6 +50,26 @@ void Arythmatik::InitInputs() {
         clk.Init(CLK_PIN);
         rst.Init(RST_PIN);
     }
+
+    // If the handler has not yet been set, assign a noop function.
+    if (ClockHandler == NULL) ClockHandler = noop;
+    if (ResetHandler == NULL) ResetHandler = noop;
+
+    // Pin Change Interrupt for CLK & RST.
+    // Thanks to Sitka Instruments for the tip and docs from https://dronebotworkshop.com/interrupts/
+    // Enable PCIE0 Bit0 = 1 (Port B)
+    PCICR |= B00000001;
+    // Enable PCINT5 & PCINT3 (Pin 13 & Pin 11)
+    PCMSK0 |= B00101000;
+    // ISR (PCINT0_vect) - ISR for Port B (D8 - D13)
+}
+
+void Arythmatik::AttachClockHandler(void (*callback)(void)) {
+    ClockHandler = callback;
+}
+
+void Arythmatik::AttachResetHandler(void (*callback)(void)) {
+    ResetHandler = callback;
 }
 
 void Arythmatik::InitOutputs() {
@@ -82,3 +107,10 @@ void Arythmatik::ProcessInputs() {
 Direction Arythmatik::EncoderDirection() {
     return Rotate(eb.increment(), config.ReverseEncoder);
 }
+
+// Define ISR
+// Pin Change Interrupt on Port B (D13 CLK & D11 RST).
+ISR(PCINT0_vect) {
+    ClockHandler();
+    ResetHandler();
+};

arythmatik.h

@@ -35,6 +35,11 @@ class Arythmatik {
     /// @brief Initializes the Arduino, and A-RYTH-MATIK hardware.
     void Init();
 
+    /// @brief Pin change handlers
+    /// @param callback 
+    void AttachClockHandler(void (*callback)(void));
+    void AttachResetHandler(void (*callback)(void)); 
+
     /// @brief Read the state of the CLK and RST inputs.
     void ProcessInputs();