Roger Weng
LT_SPI
Diff: LT_SPI.cpp
- Revision:
- 0:516e11acba42
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/LT_SPI.cpp Sun Nov 12 01:21:36 2017 +0000
@@ -0,0 +1,310 @@
+//! @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
+
+REVISION HISTORY
+$Revision: 6237 $
+$Date: 2016-12-20 15:09:16 -0800 (Tue, 20 Dec 2016) $
+
+Copyright (c) 2013, Linear Technology Corp.(LTC)
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice, this
+ list of conditions and the following disclaimer.
+2. 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.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, 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.
+
+The views and conclusions contained in the software and documentation are those
+of the authors and should not be interpreted as representing official policies,
+either expressed or implied, of Linear Technology Corp.
+
+The Linear Technology Linduino is not affiliated with the official Arduino team.
+However, the Linduino is only possible because of the Arduino team's commitment
+to the open-source community. Please, visit http://www.arduino.cc and
+http://store.arduino.cc , and consider a purchase that will help fund their
+ongoing work.
+*/
+
+//! @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 <stdint.h>
+#include "LT_SPI.h"
+
+//DigitalOut QUIKEVAL_GPIO D9; //!< Linduino QuikEval GPIO pin (QuikEval connector pin 14) connects to Arduino pin 9
+//DigitalOut QUIKEVAL_CS A3; //!< QuikEval CS pin (SPI chip select on QuikEval connector pin 6) connects to Arduino SS pin.
+//DigitalInOut QUIKEVAL_MUX_MODE_PIN(8,output); /*!< QUIKEVAL_MUX_MODE_PIN defines the control pin for the QuikEval MUX.
+//The I2C port's SCL and the SPI port's SCK signals share the same pin on the Linduino's QuikEval connector.
+//Additionally, the I2C port's SDA and the SPI port's MOSI signals share the same pin on the Linduino's QuikEval connector.
+//The pair of pins connected to the QuikEval connector is switched using a MUX on the Linduino board.
+//The control pin to switch the MUX is defined as QUIKEVAL_MUX_MODE_PIN (Arduino pin 8). */
+
+void output_low(uint8_t pin)
+{
+ pin = 0;
+}
+void output_high(uint8_t pin)
+{
+ pin = 1;
+}
+
+
+// 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.write(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.write(data_tx.b[1]); //! 2) Read MSB and send MSB
+ data_rx.b[0] = spi.write(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.write(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()
+//{
+// output_high(QUIKEVAL_CS); //! 1) Pull Chip Select High
+//
+// //! 2) Enable Main SPI
+// pinMode(QUIKEVAL_MUX_MODE_PIN, OUTPUT);
+// QUIKEVAL_MUX_MODE_PIN = 0;
+//}
+
+// 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(void) // 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.format(16,3);
+ spi.frequency(1000000);
+}
+
+// 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
+//{
+// SPDR = data; //! 1) Start the SPI transfer
+// while (!(SPSR & _BV(SPIF))); //! 2) Wait until transfer complete
+//}
+
+// 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
+//{
+// SPDR = data; //! 1) Start the SPI transfer
+// while (!(SPSR & _BV(SPIF))); //! 2) Wait until transfer complete
+// return SPDR; //! 3) Return the data read
+//}
+
+// 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);
+// }
\ No newline at end of file