Add digital in interface (#212)

Signed-off-by: Javier Balloffet <[email protected]>

andino_firmware/src/digital_in.h

@@ -0,0 +1,58 @@
+// BSD 3-Clause License
+//
+// Copyright (c) 2024, Ekumen Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this
+//    list of conditions and the following disclaimer.
+//
+// 2. Redistributions in binary form must reproduce the above copyright notice,
+//    this list of conditions and the following disclaimer in the documentation
+//    and/or other materials provided with the distribution.
+//
+// 3. Neither the name of the copyright holder nor the names of its
+//    contributors may be used to endorse or promote products derived from
+//    this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#pragma once
+
+namespace andino {
+
+/// @brief This class defines an interface for digital inputs.
+class DigitalIn {
+ public:
+  /// @brief Constructs a DigitalIn using the specified GPIO pin.
+  ///
+  /// @param gpio_pin GPIO pin.
+  explicit DigitalIn(const int gpio_pin) : gpio_pin_(gpio_pin) {}
+
+  /// @brief Destructs the digital input.
+  virtual ~DigitalIn() = default;
+
+  /// @brief Initializes the digital input.
+  virtual void begin() const = 0;
+
+  /// @brief Gets the digital input value (0 or 1).
+  ///
+  /// @return Digital input value.
+  virtual int read() const = 0;
+
+ protected:
+  /// GPIO pin.
+  const int gpio_pin_;
+};
+
+}  // namespace andino

andino_firmware/src/encoder.cpp

@@ -66,15 +66,13 @@
 
 #include <stdint.h>
 
-#include <Arduino.h>
-
-#include "pcint.h"
+#include "interrupt_in_arduino.h"
 
 namespace andino {
 
 constexpr int8_t Encoder::kTicksDelta[];
 
-const PCInt::InterruptCallback Encoder::kCallbacks[kInstancesMax] = {callback_0, callback_1};
+const InterruptIn::InterruptCallback Encoder::kCallbacks[kInstancesMax] = {callback_0, callback_1};
 
 void Encoder::callback_0() {
   if (Encoder::instances_[0] != nullptr) {
@@ -98,10 +96,10 @@ void Encoder::init() {
     return;
   }
 
-  pinMode(a_gpio_pin_, INPUT_PULLUP);
-  pinMode(b_gpio_pin_, INPUT_PULLUP);
-  andino::PCInt::attach_interrupt(a_gpio_pin_, kCallbacks[instance_count_]);
-  andino::PCInt::attach_interrupt(b_gpio_pin_, kCallbacks[instance_count_]);
+  channel_a_interrupt_in_.begin();
+  channel_a_interrupt_in_.attach(kCallbacks[instance_count_]);
+  channel_b_interrupt_in_.begin();
+  channel_b_interrupt_in_.attach(kCallbacks[instance_count_]);
 
   instances_[instance_count_] = this;
   instance_count_++;
@@ -114,7 +112,7 @@ void Encoder::reset() { count_ = 0L; }
 void Encoder::callback() {
   // Read the current channels state into the lowest 2 bits of the encoder state.
   state_ <<= 2;
-  state_ |= (digitalRead(b_gpio_pin_) << 1) | digitalRead(a_gpio_pin_);
+  state_ |= (channel_b_interrupt_in_.read() << 1) | channel_a_interrupt_in_.read();
 
   // Update the encoder count accordingly.
   count_ += kTicksDelta[(state_ & 0x0F)];

andino_firmware/src/encoder.h

@@ -66,7 +66,7 @@
 
 #include <stdint.h>
 
-#include "pcint.h"
+#include "interrupt_in_arduino.h"
 
 namespace andino {
 
@@ -79,7 +79,8 @@ class Encoder {
   ///
   /// @param a_gpio_pin Encoder channel A GPIO pin.
   /// @param b_gpio_pin Encoder channel B GPIO pin.
-  Encoder(int a_gpio_pin, int b_gpio_pin) : a_gpio_pin_(a_gpio_pin), b_gpio_pin_(b_gpio_pin) {}
+  Encoder(int a_gpio_pin, int b_gpio_pin)
+      : channel_a_interrupt_in_(a_gpio_pin), channel_b_interrupt_in_(b_gpio_pin) {}
 
   /// @brief Initializes the encoder.
   void init();
@@ -121,7 +122,7 @@ class Encoder {
   static constexpr int kInstancesMax{2};
 
   /// Static wrappers that redirect to instance callback methods.
-  static const PCInt::InterruptCallback kCallbacks[kInstancesMax];
+  static const InterruptIn::InterruptCallback kCallbacks[kInstancesMax];
 
   /// Static wrapper that redirects to the first instance callback method.
   static void callback_0();
@@ -138,11 +139,11 @@ class Encoder {
   /// Number of constructed Encoder instances.
   static int instance_count_;
 
-  /// Channel A GPIO pin.
-  int a_gpio_pin_;
+  /// Interrupt input connected to encoder channel A pin.
+  InterruptInArduino channel_a_interrupt_in_;
 
-  /// Channel B GPIO pin.
-  int b_gpio_pin_;
+  /// Interrupt input connected to encoder channel B pin.
+  InterruptInArduino channel_b_interrupt_in_;
 
   /// Encoder state. It contains both the current and previous channels state readings:
   ///   +------+-----+-----+-----+-----+-----+-----+-----+-----+

andino_firmware/src/pcint.h → andino_firmware/src/interrupt_in.h

@@ -1,6 +1,6 @@
 // BSD 3-Clause License
 //
-// Copyright (c) 2023, Ekumen Inc.
+// Copyright (c) 2024, Ekumen Inc.
 // All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
@@ -29,30 +29,28 @@
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #pragma once
 
-#include <stdint.h>
-
-#include <Arduino.h>
+#include "digital_in.h"
 
 namespace andino {
 
-/// @brief This class provides a simple way to set and use Pin Change Interrupts.
-class PCInt {
+/// @brief This class defines an interface for digital interrupt inputs.
+class InterruptIn : public DigitalIn {
  public:
   /// @brief Interrupt callback type.
   typedef void (*InterruptCallback)();
 
-  /// @brief Attaches an interrupt callback.
-  /// @note Only one callback per port is supported.
+  /// @brief Constructs a InterruptIn using the specified GPIO pin.
   ///
-  /// @param pin Pin of interest.
-  /// @param callback Callback function.
-  static void attach_interrupt(uint8_t pin, InterruptCallback callback);
+  /// @param gpio_pin GPIO pin.
+  explicit InterruptIn(const int gpio_pin) : DigitalIn(gpio_pin) {}
 
- private:
-  PCInt() = delete;
+  /// @brief Destructs the digital interrupt input.
+  virtual ~InterruptIn() = default;
 
-  /// Map between ports and Pin Change Mask registers.
-  static constexpr volatile uint8_t* kPortToPCMask[]{&PCMSK0, &PCMSK1, &PCMSK2};
+  /// @brief Attaches an interrupt callback.
+  ///
+  /// @param callback Callback function.
+  virtual void attach(InterruptCallback callback) const = 0;
 };
 
 }  // namespace andino

andino_firmware/src/pcint.cpp → andino_firmware/src/interrupt_in_arduino.cpp

@@ -1,6 +1,6 @@
 // BSD 3-Clause License
 //
-// Copyright (c) 2023, Ekumen Inc.
+// Copyright (c) 2024, Ekumen Inc.
 // All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
@@ -27,24 +27,28 @@
 // CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 // OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-#include "pcint.h"
+#include "interrupt_in_arduino.h"
 
 #include <Arduino.h>
 
-static andino::PCInt::InterruptCallback g_callbacks[3] = {nullptr};
+/// Holds the attached callbacks.
+static andino::InterruptIn::InterruptCallback g_callbacks[3] = {nullptr};
 
+/// Pin change interrupt request 0 interrupt service routine.
 ISR(PCINT0_vect) {
   if (g_callbacks[0] != nullptr) {
     g_callbacks[0]();
   }
 }
 
+/// Pin change interrupt request 1 interrupt service routine.
 ISR(PCINT1_vect) {
   if (g_callbacks[1] != nullptr) {
     g_callbacks[1]();
   }
 }
 
+/// Pin change interrupt request 2 interrupt service routine.
 ISR(PCINT2_vect) {
   if (g_callbacks[2] != nullptr) {
     g_callbacks[2]();
@@ -53,11 +57,16 @@ ISR(PCINT2_vect) {
 
 namespace andino {
 
-constexpr volatile uint8_t* PCInt::kPortToPCMask[];
+/// Map between ports and Pin Change Mask registers.
+static constexpr volatile uint8_t* kPortToPCMask[]{&PCMSK0, &PCMSK1, &PCMSK2};
 
-void PCInt::attach_interrupt(uint8_t pin, InterruptCallback callback) {
-  uint8_t bit_mask = digitalPinToBitMask(pin);
-  uint8_t port = digitalPinToPort(pin);
+void InterruptInArduino::begin() const { pinMode(gpio_pin_, INPUT_PULLUP); }
+
+int InterruptInArduino::read() const { return digitalRead(gpio_pin_); }
+
+void InterruptInArduino::attach(InterruptCallback callback) const {
+  uint8_t bit_mask = digitalPinToBitMask(gpio_pin_);
+  uint8_t port = digitalPinToPort(gpio_pin_);
 
   if (port == NOT_A_PORT) {
     return;

andino_firmware/src/interrupt_in_arduino.h

@@ -0,0 +1,51 @@
+// BSD 3-Clause License
+//
+// Copyright (c) 2024, Ekumen Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this
+//    list of conditions and the following disclaimer.
+//
+// 2. Redistributions in binary form must reproduce the above copyright notice,
+//    this list of conditions and the following disclaimer in the documentation
+//    and/or other materials provided with the distribution.
+//
+// 3. Neither the name of the copyright holder nor the names of its
+//    contributors may be used to endorse or promote products derived from
+//    this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#pragma once
+
+#include "interrupt_in.h"
+
+namespace andino {
+
+/// @brief This class provides an Arduino implementation of the digital interrupt input interface.
+class InterruptInArduino : public InterruptIn {
+ public:
+  /// @brief Constructs a InterruptInArduino using the specified GPIO pin.
+  ///
+  /// @param gpio_pin GPIO pin.
+  explicit InterruptInArduino(const int gpio_pin) : InterruptIn(gpio_pin) {}
+
+  void begin() const override;
+
+  int read() const override;
+
+  void attach(InterruptCallback callback) const override;
+};
+
+}  // namespace andino