//! @todo Review this document. /*! LT_SPI: Routines to communicate with ATmega328P's hardware SPI port. @verbatim LT_SPI implements the low level master SPI bus routines using the hardware SPI port. SPI Frequency = (CPU Clock frequency)/(16+2(TWBR)*Prescaler) SPCR = SPI Control Register (SPIE SPE DORD MSTR CPOL CPHA SPR1 SPR0) SPSR = SPI Status Register (SPIF WCOL - - - - - SPI2X) Data Modes: CPOL CPHA Leading Edge Trailing Edge 0 0 sample rising setup falling 0 1 setup rising sample falling 1 0 sample falling setup rising 1 1 sample rising setup rising CPU Frequency = 16MHz on Arduino Uno SCK Frequency SPI2X SPR1 SPR0 Frequency Uno_Frequency 0 0 0 fosc/4 4 MHz 0 0 1 fosc/16 1 MHz 0 1 0 fosc/64 250 kHz 0 1 1 fosc/128 125 kHz 0 0 0 fosc/2 8 MHz 0 0 1 fosc/8 2 MHz 0 1 0 fosc/32 500 kHz @endverbatim Copyright 2018(c) Analog Devices, Inc. All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: - Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. - Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. - Neither the name of Analog Devices, Inc. nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. - The use of this software may or may not infringe the patent rights of one or more patent holders. This license does not release you from the requirement that you obtain separate licenses from these patent holders to use this software. - Use of the software either in source or binary form, must be run on or directly connected to an Analog Devices Inc. component. THIS SOFTWARE IS PROVIDED BY ANALOG DEVICES "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL ANALOG DEVICES BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, INTELLECTUAL PROPERTY RIGHTS, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ //! @ingroup Linduino //! @{ //! @defgroup LT_SPI LT_SPI: Routines to communicate with ATmega328P's hardware SPI port. //! @} /*! @file @ingroup LT_SPI Library for LT_SPI: Routines to communicate with ATmega328P's hardware SPI port. */ #include #include #include #include "Linduino.h" #include "LT_SPI.h" // Reads and sends a byte // Return 0 if successful, 1 if failed void spi_transfer_byte(uint8_t cs_pin, uint8_t tx, uint8_t *rx) { output_low(cs_pin); //! 1) Pull CS low *rx = SPI.transfer(tx); //! 2) Read byte and send byte output_high(cs_pin); //! 3) Pull CS high } // Reads and sends a word // Return 0 if successful, 1 if failed void spi_transfer_word(uint8_t cs_pin, uint16_t tx, uint16_t *rx) { union { uint8_t b[2]; uint16_t w; } data_tx; union { uint8_t b[2]; uint16_t w; } data_rx; data_tx.w = tx; output_low(cs_pin); //! 1) Pull CS low data_rx.b[1] = SPI.transfer(data_tx.b[1]); //! 2) Read MSB and send MSB data_rx.b[0] = SPI.transfer(data_tx.b[0]); //! 3) Read LSB and send LSB *rx = data_rx.w; output_high(cs_pin); //! 4) Pull CS high } // Reads and sends a byte array void spi_transfer_block(uint8_t cs_pin, uint8_t *tx, uint8_t *rx, uint8_t length) { int8_t i; output_low(cs_pin); //! 1) Pull CS low for (i=(length-1); i >= 0; i--) rx[i] = SPI.transfer(tx[i]); //! 2) Read and send byte array output_high(cs_pin); //! 3) Pull CS high } // Connect SPI pins to QuikEval connector through the Linduino MUX. This will disconnect I2C. void quikeval_SPI_connect() { pinMode(QUIKEVAL_CS, OUTPUT); output_high(QUIKEVAL_CS); //! 1) Pull Chip Select High //! 2) Enable Main SPI pinMode(QUIKEVAL_MUX_MODE_PIN, OUTPUT); digitalWrite(QUIKEVAL_MUX_MODE_PIN, LOW); } // Configure the SPI port for 4MHz SCK. // This function or spi_enable() must be called // before using the other SPI routines. void quikeval_SPI_init(void) // Initializes SPI { spi_enable(SPI_CLOCK_DIV16); //! 1) Configure the spi port for 4MHz SCK } // Setup the processor for hardware SPI communication. // Must be called before using the other SPI routines. // Alternatively, call quikeval_SPI_connect(), which automatically // calls this function. void spi_enable(uint8_t spi_clock_divider) // Configures SCK frequency. Use constant defined in header file. { //pinMode(SCK, OUTPUT); //! 1) Setup SCK as output //pinMode(MOSI, OUTPUT); //! 2) Setup MOSI as output //pinMode(QUIKEVAL_CS, OUTPUT); //! 3) Setup CS as output SPI.begin(); SPI.setClockDivider(spi_clock_divider); } // Disable the SPI hardware port void spi_disable() { SPI.end(); } // Write a data byte using the SPI hardware void spi_write(int8_t data) // Byte to be written to SPI port { #if defined(ARDUINO_ARCH_AVR) SPDR = data; //! 1) Start the SPI transfer while (!(SPSR & _BV(SPIF))); //! 2) Wait until transfer complete #else SPI.transfer(data); #endif } // Read and write a data byte using the SPI hardware // Returns the data byte read int8_t spi_read(int8_t data) //!The data byte to be written { #if defined(ARDUINO_ARCH_AVR) SPDR = data; //! 1) Start the SPI transfer while (!(SPSR & _BV(SPIF))); //! 2) Wait until transfer complete return SPDR; //! 3) Return the data read #else return SPI.transfer(data); #endif } // Below are implementations of spi_read, etc. that do not use the // Arduino SPI library. To use these functions, uncomment them and comment out // the correcsponding function above. // // // Reads and sends a byte // // Return 0 if successful, 1 if failed // uint8_t spi_transfer_byte(uint8_t cs_pin, uint8_t tx, uint8_t *rx) // { // output_low(cs_pin); //! 1) Pull CS low // // *rx = spi_read(tx); //! 2) Read byte and send byte // // output_high(cs_pin); //! 3) Pull CS high // // return(0); // } // // // Reads and sends a word // // Return 0 if successful, 1 if failed // uint8_t spi_transfer_word(uint8_t cs_pin, uint16_t tx, uint16_t *rx) // { // union // { // uint8_t b[2]; // uint16_t w; // } data_tx; // // union // { // uint8_t b[2]; // uint16_t w; // } data_rx; // // data_tx.w = tx; // // output_low(cs_pin); //! 1) Pull CS low // // data_rx.b[1] = spi_read(data_tx.b[1]); //! 2) Read MSB and send MSB // data_rx.b[0] = spi_read(data_tx.b[0]); //! 3) Read LSB and send LSB // *rx = data_rx.w; // // output_high(cs_pin); //! 4) Pull CS high // // return(0); // } // // // Reads and sends a byte array // // Return 0 if successful, 1 if failed // uint8_t spi_transfer_block(uint8_t cs_pin, uint8_t *tx, uint8_t *rx, uint8_t length) // { // int8_t i; // // output_low(cs_pin); //! 1) Pull CS low // // for(i=0; i < length; i++) // rx[i] = spi_read(tx[i]); //! 2) Read and send byte array // // output_high(cs_pin); //! 3) Pull CS high // // return(0); // } // // // Connect SPI pins to QuikEval connector through the Linduino MUX. This will disconnect I2C. // void quikeval_SPI_connect() // { // output_high(QUIKEVAL_CS); //! 1) Pull Chip Select High // // //! 2) Enable Main SPI // pinMode(QUIKEVAL_MUX_MODE_PIN, OUTPUT); // digitalWrite(QUIKEVAL_MUX_MODE_PIN, LOW); // } // // // Configure the SPI port for 4MHz SCK. // // This function or spi_enable() must be called // // before using the other SPI routines. // void quikeval_SPI_init(void) // Initializes SPI // { // spi_enable(SPI_CLOCK_DIV32); //! 2) Configure the spi port for 4MHz SCK // } // // // Setup the processor for hardware SPI communication. // // Must be called before using the other SPI routines. // // Alternatively, call quikeval_SPI_connect(), which automatically // // calls this function. // void spi_enable(uint8_t spi_clock_divider) // Configures SCK frequency. Use constant defined in header file. // { // pinMode(SCK, OUTPUT); //! 1) Setup SCK as output // pinMode(MOSI, OUTPUT); //! 2) Setup MOSI as output // pinMode(QUIKEVAL_CS, OUTPUT); //! 3) Setup CS as output // output_low(SCK); // output_low(MOSI); // output_high(QUIKEVAL_CS); // SPCR |= _BV(MSTR); //! 4) Set the SPI port to master mode // //! 5) Set the SPI hardware rate // SPCR = (SPCR & ~SPI_CLOCK_MASK) | (spi_clock_divider & SPI_CLOCK_MASK); // SPSR = (SPSR & ~SPI_2XCLOCK_MASK) | ((spi_clock_divider >> 2) & SPI_2XCLOCK_MASK); // SPCR |= _BV(SPE); //! 5) Enable the SPI port // } // // // Disable the SPI hardware port // void spi_disable() // { // SPCR &= ~_BV(SPE); // }