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com: A spi implementation and a spi bit-banging added

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Christos Houtouridis 6 years ago
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  1. +331
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      include/utl/com/spi.h
  2. +286
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      include/utl/com/spi_bb.h

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/*!
* \file /utl/com/spi.h
* \brief An Abstract base class interface for the spi bus
*
* Copyright (C) 2018 Christos Choutouridis
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation, either version 3
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#ifndef _utl_com_spi_h__
#define _utl_com_spi_h__
#include <utl/impl/impl.h>
#include <utl/helper/crtp.h>
#include <utl/meta/sfinae.h>
namespace utl {
/*!
* \ingroup Communication
* \brief Abstract base class for spi bus
*/
//!@{
namespace spi {
/*!
* SPI implementation bit order
*/
enum class bitOrder {
LSB_First =0x01, //!< Most significant first
MSB_First =0x80 //!< Less significant first
};
/*!
* SPI implementation Clock Polarity
*/
enum class cpol {
LOW =0, //!< LOW
HIGH //!< HIGH
};
/*!
* SPI implementation Clock Phase
*/
enum class cpha {
LOW =0, //!< LOW
HIGH //!< HIGH
};
}
/*!
* Template base class for SPI communication interface using CRTP
* This class force a common interface for SPI communication
* protocol implementations.
* \param impl_t The CRTP type (the derived/implementation class typename).
*/
template <typename impl_t>
class spi_i {
_CRTP_IMPL(impl_t); //! \brief Syntactic sugar to CRTP casting
public:
using type = spi_i<impl_t>; //!< Export type as identity meta-function
/*!
* \name Object lifetime
*/
//!@{
protected:
spi_i () = default; //!< Allow constructor from derived only
~spi_i () = default; //!< Allow destructor from derived only
spi_i (const type&) = delete; //!< No copies
spi_i& operator= (const spi_i&) = delete;
//!@}
/*!
* \name Implementation requirements
* \note
* In order for the implementation to have the following as private members
* it also need to declare this class as friend
*/
//! @{
private:
uint32_t _clock () const { return impl()._clock (); } //!< clock frequency of the bus [Hz]
void _clock (uint32_t c) { impl()._clock (c); } //!< set clock frequency of the bus [Hz]
byte_t _tx_data (byte_t b) { return impl()._tx_data (b); } //!< Transmit a byte on the bus and return the response
//! @}
/*!
* \name Get/Set functions provided by the interface
*/
//!@{
public:
uint32_t clock () const { return _clock (); } //!< \return clock frequency of the bus
void clock (uint32_t c) { _clock (c); } //!< \brief set clock frequency of the bus
//!@}
/*!
* \name I/O functions provided by the interface
*/
//!@{
public:
/*!
* Transmit a byte to spi bus and return the response
*/
byte_t tx_data (byte_t out) {
return _tx_data (out);
}
/*!
* \brief
* Transmit a number of bytes to the spi bus and read the response.
* \param out Pointer to data to send to the bus
* \param in Pointer to buffer to store the data from the bus
* \param n The number of bytes to transmit/receive
* \return The number of bytes.
*/
size_t tx_data (const byte_t *out, byte_t *in, size_t n);
/*!
* Receive a byte from spi bus while transmitting 0xFF
*/
byte_t rx_data () {
return _tx_data(0xFF);
}
/*!
* \brief
* Receive a number of bytes from the spi bus while transmitting 0xFFs.
* \param in Pointer to buffer to store the data
* \param n The number of bytes to read
* \return The number of received bytes.
*/
size_t rx_data (byte_t *in, size_t n);
//!@}
};
/*!
* \brief
* Transmit a number of bytes to the spi bus and read the response.
* \param out Pointer to data to send to the bus
* \param in Pointer to buffer to store the data from the bus
* \param n The number of bytes to transmit/receive
* \return The number of bytes.
*/
template<typename _I>
size_t spi_i<_I>::tx_data (const byte_t *out, byte_t *in, size_t n) {
for (size_t nn {n} ; nn ; --nn)
*in++ = _tx_data (*out++);
return n;
}
/*!
* \brief
* Receive a number of bytes from the spi bus while transmitting 0xFFs.
* \param in Pointer to buffer to store the data
* \param n The number of bytes to read
* \return The number of received bytes.
*/
template<typename _I>
size_t spi_i<_I>::rx_data (byte_t *in, size_t n) {
for (size_t nn {n} ; nn ; --nn)
*in++ = _tx_data (0xFF);
return n;
}
/*!
* \brief
* A virtual base class implementation
* \param none
*/
template <>
class spi_i <virtual_tag> {
public:
using type = spi_i<virtual_tag>; //!< Export type as identity meta-function
/*!
* \name Object lifetime
*/
//!@{
protected:
spi_i () = default; //!< Allow constructor from derived only
spi_i (const type&) = delete; //!< No copies
type& operator= (const type&) = delete;
public:
virtual ~spi_i () = default; //!< Virtual default destructor
//!@}
/*!
* \name Implementation requirements
*/
//! @{
private:
virtual uint32_t _clock () const =0; //!< Read the clock frequency of the bus
virtual void _clock (uint32_t) =0; //!< Set the clock frequency of the bus
virtual byte_t _tx_data (byte_t) =0; //!< Transmit a byte on the bus and return the response
//! @}
/*!
* \name Get/Set functions provided by the interface
*/
//!@{
public:
uint32_t clock () const { return _clock (); } //!< \return clock frequency of the bus
void clock (uint32_t c) { _clock (c); } //!< \brief set clock frequency of the bus
//!@}
/*!
* \name I/O functions provided by the interface
*/
//!@{
public:
/*!
* Transmit a byte to spi bus and return the response
*/
byte_t tx_data (byte_t out) {
return _tx_data (out);
}
/*!
* \brief
* Transmit a number of bytes to the spi bus and read the response.
* \param out Pointer to data to send to the bus
* \param in Pointer to buffer to store the data from the bus
* \param n The number of bytes to transmit/receive
* \return The number of bytes.
*/
size_t tx_data (const byte_t *out, byte_t *in, size_t n);
/*!
* Receive a byte from spi bus while transmitting 0xFF
*/
byte_t rx_data () {
return _tx_data (0xFF);
}
/*!
* \brief
* Receive a number of bytes from the spi bus while transmitting 0xFFs.
* \param in Pointer to buffer to store the data
* \param n The number of bytes to read
* \return The number of received bytes.
*/
size_t rx_data (byte_t *in, size_t n);
//!@}
};
/*!
* \brief
* Transmit a number of bytes to the spi bus and read the response.
* \param out Pointer to data to send to the bus
* \param in Pointer to buffer to store the data from the bus
* \param n The number of bytes to transmit/receive
* \return The number of bytes.
*/
size_t spi_i<virtual_tag>::tx_data (const byte_t *out, byte_t *in, size_t n) {
for (size_t nn {n} ; nn ; --nn)
*in++ = _tx_data (*out++);
return n;
}
/*!
* \brief
* Receive a number of bytes from the spi bus while transmitting 0xFFs.
* \param in Pointer to buffer to store the data
* \param n The number of bytes to read
* \return The number of received bytes.
*/
size_t spi_i<virtual_tag>::rx_data (byte_t *in, size_t n) {
for (size_t nn {n} ; nn ; --nn)
*in++ = _tx_data (0xFF);
return n;
}
#if defined _utl_have_concepts
/*!
* i2c interface concept
*/
template <typename T>
concept bool spi_c = requires (T t, const T ct, typename T::Sequence s) {
// Object type
requires not_<std::is_copy_constructible<T>::value>::value;
requires not_<std::is_copy_assignable<T>::value>::value;
// Methods
{ct.clock()} -> uint32_t;
{t.clock(0)} -> void;
{t.tx_data(1)} -> byte_t;
{t.rx_data()} -> byte_t;
};
#else
namespace spi_i_details {
using std::declval;
template <class _Tp> using try_cclock_t= decltype (declval<const _Tp>().clock());
template <class _Tp> using try_clock_t = decltype (declval<_Tp>().clock(declval<uint32_t>()));
template <class _Tp> using try_tx_t = decltype (declval<_Tp>().tx_data(declval<byte_t>()));
template <class _Tp> using try_rx_t = decltype (declval<_Tp>().rx_data());
//! Primary template to catch any non SPI interface types
template <typename _Tp, typename =void>
struct is_spi_ : false_ {};
//! template to catch a proper SPI interface type
template <typename _Tp>
struct is_spi_ <
_Tp,
void_t <
use_if_same_t <try_cclock_t<_Tp>, uint32_t>,
use_if_same_t <try_clock_t<_Tp>, void>,
use_if_same_t <try_tx_t<_Tp>, byte_t>,
use_if_same_t <try_rx_t<_Tp>, byte_t>
>
> : true_ {};
}
/*!
* Value meta-programming function for SPI interface checking
* \param _Tp Type to check
* \return True if _Tp is a spi interface
*/
template <typename _Tp>
constexpr bool spi_c = spi_i_details::is_spi_<_Tp>::value;
#endif
//!@}
} // namespace utl
#endif /* #ifndef _utl_com_spi_h__ */

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/*!
* \file utl/com/spi_bb.h
* \brief A bit banking implementation of spi bus inherited from
* spi_i base class.
*
* Copyright (C) 2018 Christos Choutouridis
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation, either version 3
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#ifndef __utl_com_spi_bb_h__
#define __utl_com_spi_bb_h__
#include <utl/impl/impl.h>
#include <utl/helper/crtp.h>
#include <utl/meta/sfinae.h>
#include <utl/com/spi.h>
namespace utl {
/*!
* \ingroup Communication
* \brief A bit banking implementation of spi bus
* inherited from \ref spi_i base class.
* \sa spi_i
*/
//!@{
/*!
* \brief
* SPI bit banking interface template class using CRTP.
* Using the private interface we provide the interface from
* spi_i<impl_t>
*
* \param impl_t The CRTP type (the derived/implementation class typename).
* \param CPOL Clock polarity
* \param CPHA Clock phase
* \param BitOrder Data transfer bit order
*/
template <typename impl_t,
spi::cpol CPOL,
spi::cpha CPHA,
spi::bitOrder BitOrder =spi::bitOrder::MSB_First>
class spi_bb_i : public spi_i<spi_bb_i<impl_t, CPOL, CPHA, BitOrder>> {
_CRTP_IMPL(impl_t); //! \brief Syntactic sugar to CRTP casting
friend spi_i<spi_bb_i<impl_t, CPOL, CPHA, BitOrder>>;
public:
using type = spi_bb_i<impl_t, CPOL, CPHA, BitOrder>; //!< Export type as identity meta-function
/*!
* \name Object lifetime
*/
//!@{
protected:
~spi_bb_i () = default; //!< A default destructor, allow destructor from derived only
//! \brief A default constructor
spi_bb_i (uint32_t clk =1000000) noexcept
: nsec_ {1000000000/(2*clk)} {
}
//!@}
private:
//! \name SPI implementation specific functions
//!@{
template <spi::cpol C =CPOL> constexpr bool clkHigh () { return !static_cast<bool>(C); }
template <spi::cpol C =CPOL> constexpr bool clkLow () { return static_cast<bool>(C); }
template <spi::bitOrder B =BitOrder> constexpr
use_if_t <(B == spi::bitOrder::LSB_First), void> shift (byte_t& b) { b <<=1; }
template <spi::bitOrder B =BitOrder> constexpr
use_if_t <(B == spi::bitOrder::MSB_First), void> shift (byte_t& b) { b >>=1; }
//!}
/*!
* \name Implementation requirements
* \note
* In order for the implementation to have the following as private members
* it also need to declare this class as friend
*/
//!@{
private:
void MOSI (bool st) { impl().MOSI(st); } //!< Implementers's MOSI pin function
bool MISO () { return impl().MISO(); } //!< Implementers's MISO pin function
void SCLK (bool st) { impl().SCLK (st); } //!< Implementers's SCLK pin function
void delay (uint32_t nsec) { impl().delay (nsec); } //!< Implementers's half period delay function
//!@}
/*!
* \name Implementation of base requirements
*/
//!@{
private:
uint32_t _clock () const { return 1000000000/(2*nsec_); }
void _clock (uint32_t c) { nsec_ = 1000000000/(2*c); }
byte_t _tx_data (byte_t out) { return _tx_data_impl (out); }
template <spi::cpha C =CPHA>
use_if_t <(C == spi::cpha::LOW), byte_t> _tx_data_impl (byte_t out);
template <spi::cpha C =CPHA>
use_if_t <(C == spi::cpha::HIGH), byte_t> _tx_data_impl (byte_t out);
uint32_t nsec_; //!< half period of SPI bus
//!@}
};
/*!
* \brief
* _tx_data implementation for CPHA == LOW
* Out at preceding clock trailing edge, In at leading clock edge
* \param out The byte to send to SPI bus
* \return The byte read from the bus
*/
template <typename impl_t, spi::cpol CPOL, spi::cpha CPHA, spi::bitOrder BitOrder>
template <spi::cpha C>
use_if_t <(C == spi::cpha::LOW), byte_t>
spi_bb_i<impl_t, CPOL, CPHA, BitOrder>::_tx_data_impl (byte_t out) {
byte_t in {};
SCLK (clkLow());
for (uint8_t bit {static_cast<uint8_t>(BitOrder)} ; bit ; shift (bit)) {
MOSI (out & bit); // Out at preceding clock trailing edge
delay (nsec_); // Half cycle delay
SCLK (clkHigh()); // Leading edge
in |= (MISO ()) ? bit : 0; // In at leading clock edge
delay (nsec_); // Half cycle delay
SCLK (clkLow()); // Trailing edge
}
return in;
}
/*!
* \brief
* _tx_data implementation CPHA == HIGH
* Out at leading clock edge, In at trailing clock edge
* \param out The byte to send to SPI bus
* \return The byte read from the bus
*/
template <typename impl_t, spi::cpol CPOL, spi::cpha CPHA, spi::bitOrder BitOrder>
template <spi::cpha C>
use_if_t <(C == spi::cpha::HIGH), byte_t>
spi_bb_i<impl_t, CPOL, CPHA, BitOrder>::_tx_data_impl (byte_t out) {
byte_t in {};
SCLK (clkLow());
for (uint8_t bit {static_cast<uint8_t>(BitOrder)} ; bit ; shift (bit)) {
delay (nsec_); // Half cycle delay
SCLK (clkHigh()); // Leading edge
MOSI (out & bit); // Out at leading clock edge
delay (nsec_); // Half cycle delay
SCLK (clkLow()); // Trailing edge
in |= (MISO ()) ? bit : 0; // In at trailing clock edge
}
return in;
}
/*!
* \brief
* A virtual base class interface specialization.
* Using the private virtual interface we provide the interface from
* spi_i<virtual_tag>
* \param impl_t = virtual_tag
* \param CPOL Clock polarity
* \param CPHA Clock phase
* \param BitOrder Data transfer bit order
*/
template <spi::cpol CPOL,
spi::cpha CPHA,
spi::bitOrder BitOrder>
class spi_bb_i <virtual_tag, CPOL, CPHA, BitOrder> : public spi_i<virtual_tag> {
public:
using type = spi_bb_i<virtual_tag, CPOL, CPHA, BitOrder>; //!< Export type as identity meta-function
/*!
* \name Object lifetime
*/
//!@{
protected:
~spi_bb_i () = default; //!< A default destructor, allow destructor from derived only
//! \brief A default constructor
spi_bb_i (uint32_t clk =1000000) noexcept
: nsec_ {1000000000/(2*clk)} {
}
//!@}
private:
//! \name SPI implementation specific functions
//!@{
template <spi::cpol C =CPOL> constexpr bool clkHigh () { return !static_cast<bool>(C); }
template <spi::cpol C =CPOL> constexpr bool clkLow () { return static_cast<bool>(C); }
template <spi::bitOrder B =BitOrder> constexpr
use_if_t <(B == spi::bitOrder::LSB_First), void> shift (byte_t& b) { b <<=1; }
template <spi::bitOrder B =BitOrder> constexpr
use_if_t <(B == spi::bitOrder::MSB_First), void> shift (byte_t& b) { b >>=1; }
//!}
//! \name Implementation requirements
//!@{
private:
virtual void MOSI (bool) =0; //!< Implementers's MOSI pin function
virtual bool MISO () =0; //!< Implementers's MISO pin function
virtual void SCLK (bool) =0; //!< Implementers's SCLK pin function
virtual void delay (uint32_t) =0; //!< Implementers's half period delay function
//!@}
/*!
* \name Implementation of base requirements
*/
//!@{
private:
uint32_t _clock () const final { return 1000000000/(2*nsec_); }
void _clock (uint32_t c) final { nsec_ = 1000000000/(2*c); }
byte_t _tx_data (byte_t out) final { return _tx_data_impl (out); }
template <spi::cpha C =CPHA>
use_if_t <(C == spi::cpha::LOW), byte_t> _tx_data_impl (byte_t out);
template <spi::cpha C =CPHA>
use_if_t <(C == spi::cpha::HIGH), byte_t> _tx_data_impl (byte_t out);
uint32_t nsec_; //!< half period of SPI bus
//!@}
};
/*!
* \brief
* _tx_data implementation CPHA == LOW
* Out at preceding clock trailing edge, In at leading clock edge
* \param out The byte to send to SPI bus
* \return The byte read from the bus
*/
template <spi::cpol CPOL, spi::cpha CPHA, spi::bitOrder BitOrder>
template <spi::cpha C>
use_if_t <(C == spi::cpha::LOW), byte_t>
spi_bb_i<virtual_tag, CPOL, CPHA, BitOrder>::_tx_data_impl (byte_t out) {
byte_t in {};
SCLK (clkLow());
for (uint8_t bit {static_cast<uint8_t>(BitOrder)} ; bit ; shift (bit)) {
MOSI (out & bit); // Out at preceding clock trailing edge
delay (nsec_); // Half cycle delay
SCLK (clkHigh()); // Leading edge
in |= (MISO ()) ? bit : 0; // In at leading clock edge
delay (nsec_); // Half cycle delay
SCLK (clkLow()); // Trailing edge
}
return in;
}
/*!
* \brief
* _tx_data implementation CPHA == HIGH
* Out at leading clock edge, In at trailing clock edge
* \param out The byte to send to SPI bus
* \return The byte read from the bus
*/
template <spi::cpol CPOL, spi::cpha CPHA, spi::bitOrder BitOrder>
template <spi::cpha C>
use_if_t <(C == spi::cpha::HIGH), byte_t>
spi_bb_i<virtual_tag, CPOL, CPHA, BitOrder>::_tx_data_impl (byte_t out) {
byte_t in {};
SCLK (clkLow());
for (uint8_t bit {static_cast<uint8_t>(BitOrder)} ; bit ; shift (bit)) {
delay (nsec_); // Half cycle delay
SCLK (clkHigh()); // Leading edge
MOSI (out & bit); // Out at leading clock edge
delay (nsec_); // Half cycle delay
SCLK (clkLow()); // Trailing edge
in |= (MISO ()) ? bit : 0; // In at trailing clock edge
}
return in;
}
}
#endif //#ifndef __spi_bb_h__

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