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[driver] Add BitBangEncoderInput driver
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| Original file line number | Diff line number | Diff line change |
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| /* | ||
| * Copyright (c) 2021, Thomas Sommer | ||
| * | ||
| * 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/. | ||
| */ | ||
| // ---------------------------------------------------------------------------- | ||
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| #ifndef MODM_BITBANG_ENCODER_INPUT_HPP | ||
| #define MODM_BITBANG_ENCODER_INPUT_HPP | ||
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| #include <bit> | ||
| #include <modm/platform.hpp> | ||
| #include <type_traits> | ||
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| namespace modm | ||
| { | ||
| /** | ||
| * @ingroup modm_driver_bitbang_encoder_input | ||
| * @author Thomas Sommer | ||
| * | ||
| * @brief This driver decodes a AB (incremental) encoder signal | ||
| * | ||
| * @tparam SignalA First modm::platform::Gpio pin to input the encoder signal. | ||
| * @tparam SignalB Second modm::platform::Gpio pin to input the encoder signal. | ||
| * @tparam POSTSCALER n_cycles to count as one in-/decrement. | ||
| * @tparam DeltaType Must be signed integer and fit at least POSTSCALER. The Bigger | ||
| * DeltaType, the more inc-/decrements can be stored temporarily. | ||
| */ | ||
| template<typename SignalA, typename SignalB, uint8_t POSTSCALER = 4, | ||
| std::signed_integral DeltaType = int8_t> | ||
| class BitBangEncoderInput | ||
| { | ||
| static_assert(std::popcount(POSTSCALER) == 1, | ||
| "POSTSCALER must be an integer to basis 2 and not 0: 1, 2, 4, 8, 16, ..."); | ||
| static_assert(POSTSCALER <= std::numeric_limits<DeltaType>::max(), | ||
| "DeltaType is to small for POSTSCALER."); | ||
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| using Signals = modm::platform::SoftwareGpioPort<SignalA, SignalB>; | ||
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| static_assert(Signals::number_of_ports == 1, | ||
| "Signal A/B must be on the same GPIO port to prevent signal tearing!"); | ||
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| uint8_t inline getRaw(); | ||
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| public: | ||
| using ValueType = DeltaType; | ||
| BitBangEncoderInput() : raw_last(0), delta(0){}; | ||
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| // Connect SingalA and SignalB and store power-up state | ||
| inline void | ||
| connect(); | ||
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| // Call @1kHz for manual movement | ||
| inline void | ||
| update(); | ||
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| ValueType | ||
| getIncrement(); | ||
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| private: | ||
| uint8_t raw_last; | ||
| DeltaType delta; | ||
| }; | ||
| } // namespace modm | ||
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| #include "bitbang_encoder_input_impl.hpp" | ||
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| #endif // MODM_BITBANG_ENCODER_INPUT_HPP |
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| #!/usr/bin/env python3 | ||
| # -*- coding: utf-8 -*- | ||
| # | ||
| # Copyright (c) 2021, Thomas Sommer | ||
| # | ||
| # 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/. | ||
| # ----------------------------------------------------------------------------- | ||
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| def init(module): | ||
| module.name = ":driver:encoder_input.bitbang" | ||
| module.description = """ | ||
| # Quadrature Encoder Input | ||
| This driver decodes a AB (incremental) encoder signal. | ||
| Ported from code created by Peter Dannegger: | ||
| https://www.mikrocontroller.net/articles/Drehgeber. | ||
| """ | ||
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| def prepare(module, options): | ||
| module.depends(":architecture:atomic") | ||
| return True | ||
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| def build(env): | ||
| env.outbasepath = "modm/src/modm/driver/encoder" | ||
| env.copy("bitbang_encoder_input.hpp") | ||
| env.copy("bitbang_encoder_input_impl.hpp") |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,69 @@ | ||
| /* | ||
| * Copyright (c) 2021, Thomas Sommer | ||
| * | ||
| * 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/. | ||
| */ | ||
| // ---------------------------------------------------------------------------- | ||
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| #ifndef MODM_BITBANG_ENCODER_INPUT_HPP | ||
| #error "Don't include this file directly, use 'bitbang_encoder_input.hpp' instead!" | ||
| #endif | ||
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| #include <cmath> | ||
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| template<typename SignalA, typename SignalB, uint8_t POSTSCALER, | ||
| std::signed_integral DeltaType> | ||
| inline uint8_t | ||
| modm::BitBangEncoderInput<SignalA, SignalB, POSTSCALER, DeltaType>::getRaw() | ||
| { | ||
| const uint8_t read = Signals::read(); | ||
| // convert graycode to binary | ||
| uint8_t raw = 0; | ||
| if (read & 0b10) raw = 3; | ||
| if (read & 0b01) raw ^= 1; | ||
| return raw; | ||
| } | ||
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| template<typename SignalA, typename SignalB, uint8_t POSTSCALER, | ||
| std::signed_integral DeltaType> | ||
| inline void | ||
| modm::BitBangEncoderInput<SignalA, SignalB, POSTSCALER, DeltaType>::connect() | ||
| { | ||
| Signals::setInput(::Gpio::InputType::PullUp); | ||
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| // Tare power-on state | ||
| modm::delay(10us); | ||
| raw_last = getRaw(); | ||
| } | ||
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| template<typename SignalA, typename SignalB, uint8_t POSTSCALER, | ||
| std::signed_integral DeltaType> | ||
| inline void | ||
| modm::BitBangEncoderInput<SignalA, SignalB, POSTSCALER, DeltaType>::update() | ||
| { | ||
| uint8_t raw = getRaw(); | ||
| const uint8_t diff = raw_last - raw; | ||
| if (diff & 0b01) | ||
| { | ||
| raw_last = raw; | ||
| delta += (diff & 0b10) - 1; // bit 1 = direction (+/-) | ||
| } | ||
| } | ||
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| template<typename SignalA, typename SignalB, uint8_t POSTSCALER, | ||
| std::signed_integral DeltaType> | ||
| DeltaType | ||
| modm::BitBangEncoderInput<SignalA, SignalB, POSTSCALER, DeltaType>::getIncrement() | ||
| { | ||
| ::modm::atomic::Lock _; | ||
| DeltaType val = delta; | ||
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| delta &= (POSTSCALER - 1); // mask out higher bits | ||
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| constexpr uint8_t shift = std::log2(POSTSCALER); // Number of fraction bits | ||
| return val >> shift; // return whats left without fractions | ||
| } |