com: Traditionally the first module of my libs is an i2c implementation
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Christos Houtouridis
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include/utl/com/i2c.h
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285
include/utl/com/i2c.h
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/*!
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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/impl/impl.h>
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#include <utl/helper/crtp.h>
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#include <utl/meta/sfinae.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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//! uint32_t _frequency () const; < clock frequency of the bus [Hz]
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//! void _frequency (uint32_t); < set clock frequency of the bus [Hz]
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//! void _start(); < Send start functionality
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//! void _stop(); < Send stop functionality
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//! byte_t _read (bool ack, Sequence seq); < Receive a byte from the i2c bus.
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//! bool _write (byte_t byte, Sequence seq);< 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 frequency () const { return impl()._frequency (); } //!< \return clock frequency of the bus
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void frequency (uint32_t f) { impl()._frequency (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() { impl()._start (); } //!< Send start functionality
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void stop () { impl()._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 read (bool ack, Sequence seq =Sequence::BYTEnACK) {
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return impl()._read (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 write (byte_t byte, Sequence seq =Sequence::BYTEnACK) {
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return impl()._write (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 _frequency () const = 0; //!< \return clock frequency of the bus [Hz]
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virtual void _frequency (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 _read (bool ack, Sequence seq) = 0; //!< Receive a byte from the i2c bus.
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virtual bool _write (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 frequency () const { return _frequency(); } //!< \return clock frequency of the bus [Hz]
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void frequency (uint32_t f) { _frequency(f); } //!< \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 read (bool ack, Sequence seq =Sequence::BYTEnACK) {
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return _read (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 write (byte_t byte, Sequence seq =Sequence::BYTEnACK) {
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return _write (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_c = 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.frequency()} -> uint32_t;
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{t.frequency(0)} -> void;
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{t.start()} -> void;
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{t.stop()} -> void;
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{t.read (1, s)} -> byte_t;
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{t.write(0, s)} -> bool;
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};
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#else
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namespace i2c_t_cnpt {
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using std::declval;
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template <class _Tp> using try_cfreq_t = decltype (declval<const _Tp>().frequency());
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template <class _Tp> using try_freq_t = decltype (declval<_Tp>().frequency(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_read_t
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= decltype (declval<_Tp>().read (declval<bool>(), declval<typename _Tp::Sequence>()));
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template <class _Tp> using try_write_t
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= decltype (declval<_Tp>().write (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_ : 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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void_t <
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typename _Tp::Sequence,
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use_if_same_t <uint32_t,try_cfreq_t <_Tp>>,
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use_if_same_t <void, try_freq_t <_Tp>>,
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use_if_same_t <void, try_start_t <_Tp>>,
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use_if_same_t <void, try_stop_t <_Tp>>,
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use_if_same_t <byte_t, try_read_t <_Tp>>,
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use_if_same_t <bool, try_write_t <_Tp>>
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> //!^ SFINAE may apply inside if_same_t<> also
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> : 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_c = i2c_t_cnpt::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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407
include/utl/com/i2c_bb.h
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407
include/utl/com/i2c_bb.h
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/*!
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* \file utl/com/i2c_bb.h
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* \brief A bit banking implementation of i2c bus inherited from
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* i2c_i base class.
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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_bb_h__
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#define __utl_com_i2c_bb_h__
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#include <utl/impl/impl.h>
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#include <utl/helper/crtp.h>
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#include <utl/com/i2c.h>
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namespace utl {
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/*!
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* \ingroup Communication
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* \brief A bit banking implementation of i2c bus
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* inherited from \ref i2c_i base class.
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* \sa i2c_i
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*/
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//!@{
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/*!
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* \brief
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* I2C bit banking interface template class providing
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* an I2C using bit banking 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_bb_i : public i2c_i<i2c_bb_i<impl_t>> {
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_CRTP_IMPL(impl_t);
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friend i2c_i<i2c_bb_i<impl_t>>;
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public:
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using type = i2c_bb_i<impl_t>; //!< Export type as identity meta-function
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using Sequence = typename i2c_i<type>::Sequence;
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//! SDA pin direction enumerator
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enum class SDAMode {
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INPUT =0,
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OUTPUT
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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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//! \brief A default destructor, allow destructor from derived only
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~i2c_bb_i () noexcept = default;
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//! \brief A default constructor
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i2c_bb_i (uint32_t frequency =100000) noexcept
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: usec_ {1000000/(2*frequency)} { }
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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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* bool SDA (SDAMode mode, bool st);
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* void SCL (uint8_t st);
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* void delay (uint32_t usec);
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*/
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//!@{
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private:
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/*!
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* Implementers's sda pin function
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* \param st In SDA_OUTPUT mode, selects the pin output state
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* \return In SDA_INPUT mode return the pin input state
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*/
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bool SDA (SDAMode mode, bool st) { return impl().SDA (mode, st); }
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void SCL (uint8_t st) { impl().SCL (st); } //!< Implementers's scl pin function
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void delay (uint32_t usec) { impl().delay(usec); } //!< Implementers's usec delay function
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//!@}
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/*!
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* \name Implementation of base requirements
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*/
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//!@{
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private:
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uint32_t _frequency () const { return 1000000/(2*usec_); }
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void _frequency (uint32_t f) { usec_ = 1000000/(2*f); }
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void _start (); //!< Send start functionality
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void _stop (); //!< Send stop functionality
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byte_t _read (bool ack, Sequence seq);
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bool _write (byte_t byte, Sequence seq);
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uint32_t usec_; //!< half period of I2C nus
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//!@}
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};
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/*
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* ============= User functions ================
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*/
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/*!
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* \brief
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* Send a START bit to the bus
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* \return none
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*/
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template <typename impl_t>
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void i2c_bb_i<impl_t>::_start (void) {
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//Initially set pins
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SDA (SDAMode::OUTPUT, 1);
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SCL (1);
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delay (usec_);
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SDA (SDAMode::OUTPUT, 0);
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delay (usec_);
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SCL (0); //Clear Clock
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}
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/*!
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* \brief
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* Send a START bit to the bus
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* \return none
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*/
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template <typename impl_t>
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void i2c_bb_i<impl_t>::_stop (void) {
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//Stop bit Operation
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SDA (SDAMode::OUTPUT, 0);
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SCL (0);
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SCL (1);
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delay (usec_);
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SDA (SDAMode::OUTPUT, 1);
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delay (usec_);
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}
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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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template <typename impl_t>
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byte_t i2c_bb_i<impl_t>::_read (bool ack, Sequence seq) {
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byte_t byte {0};
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//Initial conditions
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SCL (0);
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SDA (SDAMode::INPUT, 0);
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if (seq == Sequence::BYTE || seq == Sequence::BYTEnACK) {
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// read 8 data bits
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for (int i=8 ; i!=0 ; --i) {
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byte <<= 1;
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SCL (1);
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delay (usec_);
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byte |= SDA (SDAMode::INPUT, 0);
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SCL (0);
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delay (usec_);
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}
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}
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if (seq == Sequence::ACK || seq == Sequence::BYTEnACK) {
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SDA (SDAMode::OUTPUT, !ack); //Send (or not) ACK bit
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SCL (1);
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delay (usec_);
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SCL (0); // Keep the bus busy
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SDA (SDAMode::OUTPUT, 0);
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}
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return byte;
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}
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/*!
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* \brief
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||||
* Transmit a byte to the i2c bus.
|
||||
* \param byte The byte to send.
|
||||
* \param seq The operation sequence to execute
|
||||
* \arg Sequence::BYTE Transmit only the byte, do not read ack bit
|
||||
* \arg Sequence::ACK Read only the ack bit
|
||||
* \arg Sequence::BYTEnACK Transmit the byte and read the ack bit
|
||||
* \return Slave's ACK bit
|
||||
* \arg false Slave didn't ACK
|
||||
* \arg true Slave did ACK
|
||||
*/
|
||||
template <typename impl_t>
|
||||
bool i2c_bb_i<impl_t>::_write (byte_t byte, Sequence seq) {
|
||||
bool ack {false};
|
||||
//Initial conditions
|
||||
SCL (0);
|
||||
SDA (SDAMode::OUTPUT, 0);
|
||||
|
||||
if (seq == Sequence::BYTE || seq == Sequence::BYTEnACK) {
|
||||
//Send 8 bit data
|
||||
for (int i=8 ; i!=0 ; --i) {
|
||||
//Send MSB
|
||||
SDA (SDAMode::OUTPUT, byte & 0x80);
|
||||
byte <<= 1;
|
||||
SCL (1);
|
||||
delay (usec_);
|
||||
SCL (0);
|
||||
delay (usec_);
|
||||
}
|
||||
}
|
||||
if (seq == Sequence::ACK || seq == Sequence::BYTEnACK) {
|
||||
// Get ACK
|
||||
SDA (SDAMode::INPUT, 0);
|
||||
SCL (1);
|
||||
delay (usec_);
|
||||
ack = !SDA (SDAMode::INPUT, 0);
|
||||
SCL (0); // Keep the bus busy
|
||||
delay (usec_);
|
||||
SDA (SDAMode::OUTPUT, 0);
|
||||
}
|
||||
return ack;
|
||||
}
|
||||
|
||||
|
||||
/*!
|
||||
* \brief
|
||||
* A virtual base class interface specialization.
|
||||
* Using the private virtual interface we provide the interface from
|
||||
* i2c_i<virtual_tag>
|
||||
* \param impl_t = virtual_tag
|
||||
*/
|
||||
template<>
|
||||
class i2c_bb_i<virtual_tag> : public i2c_i<virtual_tag> {
|
||||
public:
|
||||
using type = i2c_bb_i<virtual_tag>; //!< Export type as identity meta-function
|
||||
using Sequence = typename i2c_i<virtual_tag>::Sequence;
|
||||
//! SDA pin direction enumerator
|
||||
enum class SDAMode {
|
||||
INPUT =0,
|
||||
OUTPUT
|
||||
};
|
||||
|
||||
/*!
|
||||
* \name Object lifetime
|
||||
*/
|
||||
//!@{
|
||||
protected:
|
||||
//! \brief Constructor
|
||||
i2c_bb_i (uint32_t frequency =100000) noexcept
|
||||
: usec_ {1000000/(2*frequency)} { }
|
||||
//! \brief Virtual destructor
|
||||
virtual ~i2c_bb_i () noexcept = default;
|
||||
//!@}
|
||||
|
||||
/*!
|
||||
* \name Implementation requirements
|
||||
*/
|
||||
//!@{
|
||||
private:
|
||||
/*!
|
||||
* Implementers's sda pin function
|
||||
* \param st In SDA_OUTPUT mode, selects the pin output state
|
||||
* \return In SDA_INPUT mode return the pin input state
|
||||
*/
|
||||
virtual bool SDA (SDAMode mode, bool st) =0;
|
||||
virtual void SCL (bool st) =0; //!< Implementers's scl pin function
|
||||
virtual void delay (uint32_t usec) =0; //!< Implementers's usec delay function
|
||||
//!@}
|
||||
|
||||
/*!
|
||||
* \name Implementation of base requirements
|
||||
*/
|
||||
//!@{
|
||||
private:
|
||||
uint32_t _frequency () const final { return 1000000/(2*usec_); }
|
||||
void _frequency (uint32_t f) final { usec_ = 1000000/(2*f); }
|
||||
|
||||
void _start () final;
|
||||
void _stop () final;
|
||||
byte_t _read (bool ack, Sequence seq) final;
|
||||
bool _write (byte_t byte, Sequence seq) final;
|
||||
//!< half period of I2C bus
|
||||
uint32_t usec_;
|
||||
//!@}
|
||||
};
|
||||
|
||||
/*!
|
||||
* \brief
|
||||
* Send a START bit to the bus
|
||||
* \return none
|
||||
*/
|
||||
void i2c_bb_i<virtual_tag>::_start (void) {
|
||||
//Initially set pins
|
||||
SDA (SDAMode::OUTPUT, 1);
|
||||
SCL (1);
|
||||
delay (usec_);
|
||||
SDA (SDAMode::OUTPUT, 0);
|
||||
delay (usec_);
|
||||
SCL (0); //Clear Clock
|
||||
}
|
||||
|
||||
/*!
|
||||
* \brief
|
||||
* Send a START bit to the bus
|
||||
* \return none
|
||||
*/
|
||||
void i2c_bb_i<virtual_tag>::_stop (void) {
|
||||
//Stop bit Operation
|
||||
SDA (SDAMode::OUTPUT, 0);
|
||||
SCL (0);
|
||||
SCL (1);
|
||||
delay (usec_);
|
||||
SDA (SDAMode::OUTPUT, 1);
|
||||
delay (usec_);
|
||||
}
|
||||
|
||||
/*!
|
||||
* \brief
|
||||
* Receive a byte from the i2c bus.
|
||||
* \param ack Optional ack bit.
|
||||
* \arg 1 ACK the reception
|
||||
* \arg 0 Don't ACK the reception.
|
||||
* \param seq The operation sequence to execute
|
||||
* \arg Sequence::BYTE Receive only the byte, do not send ack clock
|
||||
* \arg Sequence::ACK Send only the ack bit
|
||||
* \arg Sequence::BYTEnACK Receive the byte and send the ack bit
|
||||
* \return The byte received.
|
||||
*/
|
||||
byte_t i2c_bb_i<virtual_tag>::_read (bool ack, Sequence seq) {
|
||||
byte_t byte {0};
|
||||
//Initial conditions
|
||||
SCL (0);
|
||||
SDA (SDAMode::INPUT, 0);
|
||||
|
||||
if (seq == Sequence::BYTE || seq == Sequence::BYTEnACK) {
|
||||
// read 8 data bits
|
||||
for (int i=8 ; i!=0 ; --i) {
|
||||
byte <<= 1;
|
||||
SCL (1);
|
||||
delay (usec_);
|
||||
byte |= SDA (SDAMode::INPUT, 0);
|
||||
SCL (0);
|
||||
delay (usec_);
|
||||
}
|
||||
}
|
||||
if (seq == Sequence::ACK || seq == Sequence::BYTEnACK) {
|
||||
SDA (SDAMode::OUTPUT, !ack); //Send (or not) ACK bit
|
||||
SCL (1);
|
||||
delay (usec_);
|
||||
SCL (0); // Keep the bus busy
|
||||
SDA (SDAMode::OUTPUT, 0);
|
||||
}
|
||||
return byte;
|
||||
}
|
||||
|
||||
/*!
|
||||
* \brief
|
||||
* Transmit a byte to the i2c bus.
|
||||
* \param byte The byte to send.
|
||||
* \param seq The operation sequence to execute
|
||||
* \arg Sequence::BYTE Transmit only the byte, do not read ack bit
|
||||
* \arg Sequence::ACK Read only the ack bit
|
||||
* \arg Sequence::BYTEnACK Transmit the byte and read the ack bit
|
||||
* \return Slave's ACK bit
|
||||
* \arg false Slave didn't ACK
|
||||
* \arg true Slave did ACK
|
||||
*/
|
||||
bool i2c_bb_i<virtual_tag>::_write (byte_t byte, Sequence seq) {
|
||||
bool ack {false};
|
||||
//Initial conditions
|
||||
SCL (0);
|
||||
SDA (SDAMode::OUTPUT, 0);
|
||||
|
||||
if (seq == Sequence::BYTE || seq == Sequence::BYTEnACK) {
|
||||
//Send 8 bit data
|
||||
for (int i=8 ; i!=0 ; --i) {
|
||||
//Send MSB
|
||||
SDA (SDAMode::OUTPUT, byte & 0x80);
|
||||
byte <<= 1;
|
||||
SCL (1);
|
||||
delay (usec_);
|
||||
SCL (0);
|
||||
delay (usec_);
|
||||
}
|
||||
}
|
||||
if (seq == Sequence::ACK || seq == Sequence::BYTEnACK) {
|
||||
// Get ACK
|
||||
SDA (SDAMode::INPUT, 0);
|
||||
SCL (1);
|
||||
delay (usec_);
|
||||
ack = !SDA (SDAMode::INPUT, 0);
|
||||
SCL (0); // Keep the bus busy
|
||||
delay (usec_);
|
||||
SDA (SDAMode::OUTPUT, 0);
|
||||
}
|
||||
return ack;
|
||||
}
|
||||
//!@}
|
||||
|
||||
} // namspace utl
|
||||
|
||||
|
||||
#endif // #ifndef __utl_com_i2c_bb_h__
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user