Add driver for AB (incremental) encoder output

README.md

@@ -190,56 +190,58 @@ can easily configure them for you specific needs.
 <td align="center">DS1631</td>
 <td align="center">DS18B20</td>
 <td align="center">EA-DOG</td>
+<td align="center">ENCODER-OUTPUT</td>
 <td align="center">FT245</td>
-<td align="center">FT6X06</td>
 </tr><tr>
+<td align="center">FT6X06</td>
 <td align="center">HCLAx</td>
 <td align="center">HD44780</td>
 <td align="center">HMC58x</td>
 <td align="center">HMC6343</td>
 <td align="center">HX711</td>
-<td align="center">I2C-EEPROM</td>
 </tr><tr>
+<td align="center">I2C-EEPROM</td>
 <td align="center">ITG3200</td>
 <td align="center">L3GD20</td>
 <td align="center">LAWICEL</td>
 <td align="center">LIS302DL</td>
 <td align="center">LIS3DSH</td>
-<td align="center">LM75</td>
 </tr><tr>
+<td align="center">LM75</td>
 <td align="center">LP503X</td>
 <td align="center">LSM303A</td>
 <td align="center">LTC2984</td>
 <td align="center">MAX6966</td>
 <td align="center">MAX7219</td>
-<td align="center">MCP23X17</td>
 </tr><tr>
+<td align="center">MCP23X17</td>
 <td align="center">MCP2515</td>
 <td align="center">NOKIA5110</td>
 <td align="center">NRF24</td>
 <td align="center">TFT-DISPLAY</td>
 <td align="center">PAT9125EL</td>
-<td align="center">PCA8574</td>
 </tr><tr>
+<td align="center">PCA8574</td>
 <td align="center">PCA9535</td>
 <td align="center">PCA9548A</td>
 <td align="center">PCA9685</td>
 <td align="center">SIEMENS-S65</td>
 <td align="center">SIEMENS-S75</td>
-<td align="center">SK6812</td>
 </tr><tr>
+<td align="center">SK6812</td>
 <td align="center">SK9822</td>
 <td align="center">SSD1306</td>
 <td align="center">SX1276</td>
 <td align="center">TCS3414</td>
 <td align="center">TCS3472</td>
-<td align="center">TLC594X</td>
 </tr><tr>
+<td align="center">TLC594X</td>
 <td align="center">TMP102</td>
 <td align="center">TMP175</td>
 <td align="center">VL53L0</td>
 <td align="center">VL6180</td>
 <td align="center">WS2812</td>
+</tr><tr>
 </tr>
 </table>
 <!--/drivertable-->

examples/stm32f4_discovery/encoder_output/main.cpp

@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2020, Raphael Lehmann
+ *
+ * This file is part of the modm project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+// ----------------------------------------------------------------------------
+
+#include <modm/board.hpp>
+#include <modm/driver/encoder/encoder_output.hpp>
+
+using namespace Board;
+
+// ----------------------------------------------------------------------------
+int
+main()
+{
+
+	initialize();
+
+	LedBlue::set();
+	LedGreen::set();
+
+	// period=100000 // 100000us => 10Hz (visible)
+	using TestEncoder = modm::EncoderOutput<LedBlue, LedGreen, int32_t, modm::PrecisePeriodicTimer, 100'000>;
+	TestEncoder testEncoder{0};
+
+	testEncoder.setPosition(1 << 31);
+	while (1)
+	{
+		testEncoder.update();
+		LedRed::toggle();
+	}
+
+	return 0;
+}

examples/stm32f4_discovery/encoder_output/project.xml

@@ -0,0 +1,10 @@
+<library>
+  <extends>modm:disco-f407vg</extends>
+  <options>
+    <option name="modm:build:build.path">../../../build/stm32f4_discovery/encoder_output</option>
+  </options>
+  <modules>
+    <module>modm:driver:encoder.output</module>
+    <module>modm:build:scons</module>
+  </modules>
+</library>

src/modm/driver/encoder/encoder_output.hpp

@@ -0,0 +1,86 @@
+// coding: utf-8
+/*
+ * Copyright (c) 2019, Raphael Lehmann
+ *
+ * This file is part of the modm project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+// ----------------------------------------------------------------------------
+
+#ifndef MODM_ENCODER_OUTPUT_HPP
+#define MODM_ENCODER_OUTPUT_HPP
+
+#include <modm/processing/timer/periodic_timer.hpp>
+
+namespace modm
+{
+
+/**
+ * @ingroup modm_driver_encoder_output
+ * @author  Raphael Lehmann
+ *
+ * @brief                This driver generates a AB (incremental) encoder signal to
+ *                         emulate a hardware encoder with a microcontroller.
+ *
+ * @tparam PinA          First modm::platform::Gpio pin to output the encoder signal.
+ * @tparam PinB          Second modm::platform::Gpio pin to output the encoder signal.
+ * @tparam PositionType  Data type (integer) of the position value, default `int32_t`.
+ * @tparam PeriodicTimer Defaults to `modm::PeriodicTimer`, must be replaced for
+ *                         encoder frequencies above 1kHz by a class that offers
+ *                         time steps less than 1ms, e.g. `modm::PrecisePeriodicTimer`.
+ * @tparam period        Timebase for the output signal. This limits the maximal
+ *                         frequency of the encoder signal. Defaults to `1`.
+ */
+template <
+	class PinA,
+	class PinB,
+	typename PositionType = int32_t,
+	class PeriodicTimer = modm::PeriodicTimer,
+	uint32_t period = 1
+	>
+class EncoderOutput {
+public:
+	/**
+	 * @brief Initializes the Encoder.
+	 *
+	 * Sets pins (PinA and PinB) as output pins.
+	 *
+	 * @param initialValue for the encoder. Useful with unsigned PositionType
+	 *          data types. Defaults to 0.
+	 */
+	EncoderOutput(PositionType initialValue);
+
+	/**
+	 * @brief Update method. Generates the encoder signal.
+	 *
+	 * Call this function in your main loop.
+	 */
+	void update();
+
+	/**
+	 * @brief Set the position for the encoder.
+	 * @param position The position setpoint for the encoder.
+	 */
+	void setPosition(PositionType position) { setpoint = position; };
+
+private:
+	PositionType setpoint;
+	PositionType actualValue;
+	PeriodicTimer timer;
+	enum class State : uint8_t {
+		State0,
+		State1,
+		State2,
+		State3,
+	};
+	State state;
+};
+
+}
+
+#include "encoder_output_impl.hpp"
+
+#endif

src/modm/driver/encoder/encoder_output.lb

@@ -0,0 +1,33 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+#
+# Copyright (c) 2019, Raphael Lehmann
+#
+# This file is part of the modm project.
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+# -----------------------------------------------------------------------------
+
+
+def init(module):
+    module.parent = "driver"
+    module.name = "encoder.output"
+    module.description = """\
+# Encoder Output
+
+This driver generates a AB (incremental) encoder signal to
+emulate a hardware encoder with a microcontroller.
+"""
+
+def prepare(module, options):
+    module.depends(
+        ":architecture:gpio",
+        ":processing:timer")
+    return True
+
+def build(env):
+    env.outbasepath = "modm/src/modm/driver/encoder"
+    env.copy("encoder_output.hpp")
+    env.copy("encoder_output_impl.hpp")

src/modm/driver/encoder/encoder_output_impl.hpp

@@ -0,0 +1,92 @@
+// coding: utf-8
+/*
+ * Copyright (c) 2019, Raphael Lehmann
+ *
+ * This file is part of the modm project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+// ----------------------------------------------------------------------------
+
+#ifndef	MODM_ENCODER_OUTPUT_HPP
+#	error	"Don't include this file directly, use 'encoder_output.hpp' instead!"
+#endif
+#include "encoder_output.hpp"
+
+template <
+	class PinA,
+	class PinB,
+	typename PositionType,
+	class PeriodicTimer,
+	uint32_t period
+	>
+modm::EncoderOutput<PinA, PinB, PositionType, PeriodicTimer, period>::EncoderOutput(PositionType initialValue) :
+	setpoint(initialValue), actualValue(initialValue), timer(period), state(State::State0)
+{
+	PinA::setOutput();
+	PinB::setOutput();
+	PinA::set();
+	PinB::set();
+	setpoint = initialValue;
+	actualValue = initialValue;
+}
+
+template <
+	class PinA,
+	class PinB,
+	typename PositionType,
+	class PeriodicTimer,
+	uint32_t period
+	>
+void
+modm::EncoderOutput<PinA, PinB, PositionType, PeriodicTimer, period>::update()
+{
+	if(timer.execute()){
+		if(setpoint > actualValue) {
+			// generate forward tick
+			switch(state) {
+				case State::State0:
+					PinA::reset();
+					state = State::State1;
+					break;
+				case State::State1:
+					PinB::reset();
+					state = State::State2;
+					break;
+				case State::State2:
+					PinA::set();
+					state = State::State3;
+					break;
+				case State::State3:
+					PinB::set();
+					state = State::State0;
+					break;
+			}
+			actualValue++;
+		}
+		else if(setpoint < actualValue) {
+			// generate backward tick
+			switch(state) {
+				case State::State0:
+					PinB::reset();
+					state = State::State3;
+					break;
+				case State::State1:
+					PinA::reset();
+					state = State::State0;
+					break;
+				case State::State2:
+					PinB::set();
+					state = State::State1;
+					break;
+				case State::State3:
+					PinA::set();
+					state = State::State2;
+					break;
+			}
+			actualValue--;
+		}
+	}
+}