287 lines
10 KiB
C++
287 lines
10 KiB
C++
/*!
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* \file /utl/com/i2c.h
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* \brief An Abstract base class interface for the i2c bus
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*
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* Copyright (C) 2018 Christos Choutouridis
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as
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* published by the Free Software Foundation, either version 3
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#ifndef _utl_com_i2c_h__
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#define _utl_com_i2c_h__
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#include <utl/core/impl.h>
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#include <utl/core/crtp.h>
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#include <utl/meta/meta.h>
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namespace utl {
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/*!
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* \ingroup Communication
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* \brief Abstract base class for i2c bus
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*/
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//!@{
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/*!
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* \brief
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* this class force a common interface for I2C communication
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* protocol implementations using CRTP
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* \param impl_t The CRTP type (the derived/implementation class typename).
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*/
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template <typename impl_t>
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class i2c_i {
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_CRTP_IMPL(impl_t);
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public:
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using type = i2c_i<impl_t>; //!< Export type as identity meta-function
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//! I2C transmit/receive sequence
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enum class Sequence {
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BYTE =0, //!< Only read/write byte [8 clocks]
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ACK, //!< Only send/receive ack [1 clock]
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BYTEnACK //!< Read/Write byte and ack [9 clocks]
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};
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/*!
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* \name Object lifetime
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*/
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//!@{
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protected:
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i2c_i () = default; //!< Allow constructor from derived only
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~i2c_i () = default; //!< Allow destructor from derived only
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i2c_i (const type&) = delete; //!< No copies
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type& operator= (const type&) = delete;
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//!@}
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/*!
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* \name Implementation requirements
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* \note
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* In order for the implementation to have the following as private members
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* it also need to declare this class as friend
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*/
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//!@{
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private:
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uint32_t _clock () const { return impl()._clock (); } //!< clock frequency of the bus [Hz]
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void _clock (uint32_t c) { impl()._clock (c); } //!< set clock frequency of the bus [Hz]
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void _start() { impl()._start (); } //!< Send start functionality
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void _stop() { impl()._stop (); } //!< Send stop functionality
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byte_t _rx_data (bool ack, Sequence seq) { return impl()._rx_data (ack, seq); }
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bool _tx_data (byte_t byte, Sequence seq) { return impl()._tx_data (byte, seq); }
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//!@}
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/*!
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* \name Get/Set functions
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*/
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//!@{
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public:
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uint32_t clock () const { return _clock (); } //!< \return clock frequency of the bus
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void clock (uint32_t f) { _clock (f); } //!< \brief set clock frequency of the bus
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//!@}
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/*!
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* \name User functions
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*/
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//!@{
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public:
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void start() { _start (); } //!< Send start functionality
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void stop () { _stop (); } //!< Send stop functionality
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/*!
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* \brief
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* Receive a byte from the i2c bus.
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* \param ack Optional ack bit.
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* \arg 1 ACK the reception
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* \arg 0 Don't ACK the reception.
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* \param seq The operation sequence to execute
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* \arg Sequence::BYTE Receive only the byte, do not send ack clock
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* \arg Sequence::ACK Send only the ack bit
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* \arg Sequence::BYTEnACK Receive the byte and send the ack bit
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* \return The byte received.
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*/
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byte_t rx_data (bool ack, Sequence seq =Sequence::BYTEnACK) {
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return _rx_data (ack, seq);
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}
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/*!
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* \brief
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* Transmit a byte to the i2c bus.
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* \param byte The byte to send.
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* \param seq The operation sequence to execute
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* \arg Sequence::BYTE Transmit only the byte, do not read ack bit
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* \arg Sequence::ACK Read only the ack bit
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* \arg Sequence::BYTEnACK Transmit the byte and read the ack bit
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* \return Slave's ACK bit
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* \arg false Slave didn't ACK
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* \arg true Slave did ACK
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*/
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bool tx_data (byte_t byte, Sequence seq =Sequence::BYTEnACK) {
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return _tx_data (byte, seq);
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}
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//!@}
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};
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/*!
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* \brief
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* A virtual base class specialization
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* \param impl_t = virtual_tag
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*/
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template<>
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class i2c_i <virtual_tag> {
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public:
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using type = i2c_i <virtual_tag>; //!< Export type as identity meta-function
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//! I2C transmit/receive sequence
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enum class Sequence {
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BYTE=0, //!< Only read/write byte [8 clocks]
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ACK, //!< Only send/receive ack [1 clock]
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BYTEnACK //!< Read/Write byte and ack [9 clocks]
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};
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/*!
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* \name Object lifetime
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*/
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//!@{
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protected:
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i2c_i () = default; //!< Allow constructor from derived only
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i2c_i (const type&) = delete; //!< No copies
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type& operator= (const type&) = delete;
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public:
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virtual ~i2c_i () = default; //!< Virtual default destructor
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//!@}
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/*!
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* \name Implementation requirements
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*/
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//!@{
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private:
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virtual uint32_t _clock () const = 0; //!< \return clock frequency of the bus [Hz]
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virtual void _clock (uint32_t) = 0; //!< \brief set clock frequency of the bus [Hz]
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virtual void _start() = 0; //!< Send start functionality
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virtual void _stop() = 0; //!< Send stop functionality
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virtual byte_t _rx_data (bool ack, Sequence seq) = 0; //!< Receive a byte from the i2c bus.
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virtual bool _tx_data (byte_t byte, Sequence seq) = 0; //!< Transmit a byte to the i2c bus.
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//!@}
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/*!
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* \name Get/Set functions
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*/
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//!@{
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public:
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uint32_t clock () const { return _clock(); } //!< \return clock frequency of the bus [Hz]
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void clock (uint32_t c) { _clock(c); } //!< \brief set clock frequency of the bus [Hz]
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//!@}
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/*!
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* \name User functions
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*/
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//!@{
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public:
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void start () { _start(); }
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void stop () { _stop(); }
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/*!
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* \brief
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* Receive a byte from the i2c bus.
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* \param ack Optional ack bit.
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* \arg 1 ACK the reception
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* \arg 0 Don't ACK the reception.
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* \param seq The operation sequence to execute
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* \arg Sequence::BYTE Receive only the byte, do not send ack clock
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* \arg Sequence::ACK Send only the ack bit
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* \arg Sequence::BYTEnACK Receive the byte and send the ack bit
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* \return The byte received.
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*/
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byte_t rx_data (bool ack, Sequence seq =Sequence::BYTEnACK) {
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return _rx_data (ack, seq);
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}
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/*!
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* \brief
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* Transmit a byte to the i2c bus.
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* \param byte The byte to send.
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* \param seq The operation sequence to execute
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* \arg Sequence::BYTE Transmit only the byte, do not read ack bit
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* \arg Sequence::ACK Read only the ack bit
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* \arg Sequence::BYTEnACK Transmit the byte and read the ack bit
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* \return Slave's ACK bit
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* \arg false Slave didn't ACK
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* \arg true Slave did ACK
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*/
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bool tx_data (byte_t byte, Sequence seq =Sequence::BYTEnACK) {
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return _tx_data (byte, seq);
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}
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//!@}
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};
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#if defined _utl_have_concepts
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/*!
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* i2c interface concept
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*/
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template <typename T>
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concept bool I2c_i = requires (T t, const T ct, typename T::Sequence s) {
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// Object type
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requires not_<std::is_copy_constructible<T>::value>::value;
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requires not_<std::is_copy_assignable<T>::value>::value;
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// Methods
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{ct.clock()} -> uint32_t;
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{t.clock(0)} -> void;
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{t.start()} -> void;
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{t.stop()} -> void;
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{t.rx_data (1, s)} -> byte_t;
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{t.tx_data (0, s)} -> bool;
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};
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#else
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namespace i2c_i_details {
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using std::declval;
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template <class _Tp> using try_cclk_t = decltype (declval<const _Tp>().clock());
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template <class _Tp> using try_clk_t = decltype (declval<_Tp>().clock(declval<uint32_t>()));
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template <class _Tp> using try_start_t = decltype (declval<_Tp>().start());
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template <class _Tp> using try_stop_t = decltype (declval<_Tp>().stop());
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template <class _Tp> using try_rx_data_t
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= decltype (declval<_Tp>().rx_data (declval<bool>(), declval<typename _Tp::Sequence>()));
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template <class _Tp> using try_tx_data_t
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= decltype (declval<_Tp>().tx_data (declval<byte_t>(), declval<typename _Tp::Sequence>()));
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//! Primary template to catch any non I2C interface types
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template <typename _Tp, typename =void>
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struct is_i2c_ : meta::false_ { };
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//! template to catch a proper I2C interface type
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template <typename _Tp>
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struct is_i2c_ <_Tp,
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meta::void_t <
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typename _Tp::Sequence,
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meta::use_if_same_t <uint32_t,try_cclk_t <_Tp>>,
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meta::use_if_same_t <void, try_clk_t <_Tp>>,
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meta::use_if_same_t <void, try_start_t <_Tp>>,
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meta::use_if_same_t <void, try_stop_t <_Tp>>,
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meta::use_if_same_t <byte_t, try_rx_data_t <_Tp>>,
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meta::use_if_same_t <bool, try_tx_data_t <_Tp>>
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>
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> : meta::true_ { };
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}
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/*!
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* Value meta-programming function alias for I2C interface checking
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* \param _Tp Type to check
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* \return True if _Tp is a i2c interface
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*/
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// template <typename _Tp>
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// constexpr bool I2c_i = i2c_i_details::is_i2c_<_Tp>::value;
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#endif
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//!@}
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} // namespace utl
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#endif // _utl_com_i2c_h__
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