Initial Arduino IDE based on Processing.

build/shared/lib/avrlib/spi.c

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+/*! \file spi.c \brief SPI interface driver. */
+//*****************************************************************************
+//
+// File Name	: 'spi.c'
+// Title		: SPI interface driver
+// Author		: Pascal Stang - Copyright (C) 2000-2002
+// Created		: 11/22/2000
+// Revised		: 06/06/2002
+// Version		: 0.6
+// Target MCU	: Atmel AVR series
+// Editor Tabs	: 4
+//
+// NOTE: This code is currently below version 1.0, and therefore is considered
+// to be lacking in some functionality or documentation, or may not be fully
+// tested.  Nonetheless, you can expect most functions to work.
+//
+// This code is distributed under the GNU Public License
+//		which can be found at http://www.gnu.org/licenses/gpl.txt
+//
+//*****************************************************************************
+
+#include <avr/io.h>
+#include <avr/signal.h>
+#include <avr/interrupt.h>
+
+#include "spi.h"
+
+// Define the SPI_USEINT key if you want SPI bus operation to be
+// interrupt-driven.  The primary reason for not using SPI in
+// interrupt-driven mode is if the SPI send/transfer commands
+// will be used from within some other interrupt service routine
+// or if interrupts might be globally turned off due to of other
+// aspects of your program
+//
+// Comment-out or uncomment this line as necessary
+#define SPI_USEINT
+
+// global variables
+volatile u08 spiTransferComplete;
+
+// SPI interrupt service handler
+#ifdef SPI_USEINT
+SIGNAL(SIG_SPI)
+{
+	spiTransferComplete = TRUE;
+}
+#endif
+
+// access routines
+void spiInit()
+{
+#ifdef __AVR_ATmega128__
+	// setup SPI I/O pins
+	sbi(PORTB, 1);	// set SCK hi
+	sbi(DDRB, 1);	// set SCK as output
+	cbi(DDRB, 3);	// set MISO as input
+	sbi(DDRB, 2);	// set MOSI as output
+	sbi(DDRB, 0);	// SS must be output for Master mode to work
+#else
+	// setup SPI I/O pins
+	sbi(PORTB, 7);	// set SCK hi
+	sbi(DDRB, 7);	// set SCK as output
+	cbi(DDRB, 6);	// set MISO as input
+	sbi(DDRB, 5);	// set MOSI as output
+	sbi(DDRB, 4);	// SS must be output for Master mode to work
+#endif
+	
+	// setup SPI interface :
+	// master mode
+	sbi(SPCR, MSTR);
+	// clock = f/4
+//	cbi(SPCR, SPR0);
+//	cbi(SPCR, SPR1);
+	// clock = f/16
+	cbi(SPCR, SPR0);
+	sbi(SPCR, SPR1);
+	// select clock phase positive-going in middle of data
+	cbi(SPCR, CPOL);
+	// Data order MSB first
+	cbi(SPCR,DORD);
+	// enable SPI
+	sbi(SPCR, SPE);
+		
+	
+	// some other possible configs
+	//outp((1<<MSTR)|(1<<SPE)|(1<<SPR0), SPCR );
+	//outp((1<<CPHA)|(1<<CPOL)|(1<<MSTR)|(1<<SPE)|(1<<SPR0)|(1<<SPR1), SPCR );
+	//outp((1<<CPHA)|(1<<MSTR)|(1<<SPE)|(1<<SPR0), SPCR );
+	
+	// clear status
+	inb(SPSR);
+	spiTransferComplete = TRUE;
+
+	// enable SPI interrupt
+	#ifdef SPI_USEINT
+	sbi(SPCR, SPIE);
+	#endif
+}
+/*
+void spiSetBitrate(u08 spr)
+{
+	outb(SPCR, (inb(SPCR) & ((1<<SPR0)|(1<<SPR1))) | (spr&((1<<SPR0)|(1<<SPR1)))));
+}
+*/
+void spiSendByte(u08 data)
+{
+	// send a byte over SPI and ignore reply
+	#ifdef SPI_USEINT
+		while(!spiTransferComplete);
+	#else
+		while(!(inb(SPSR) & (1<<SPIF)));
+	#endif
+
+	spiTransferComplete = FALSE;
+	outb(SPDR, data);
+}
+
+u08 spiTransferByte(u08 data)
+{
+	// make sure interface is idle
+	#ifdef SPI_USEINT
+		while(!spiTransferComplete);
+	#else
+		while(!(inb(SPSR) & (1<<SPIF)));
+	#endif
+
+	// send the given data
+	spiTransferComplete = FALSE;
+	outb(SPDR, data);
+
+	// wait for transfer to complete
+	#ifdef SPI_USEINT
+		while(!spiTransferComplete);
+	#else
+		while(!(inb(SPSR) & (1<<SPIF)));
+		// *** reading of the SPSR and SPDR are crucial
+		// *** to the clearing of the SPIF flag
+		// *** in non-interrupt mode
+		//inb(SPDR);
+		// set flag
+		spiTransferComplete = TRUE;
+	#endif
+	// return the received data
+	return inb(SPDR);
+}
+
+u16 spiTransferWord(u16 data)
+{
+	u16 rxData = 0;
+
+	// send MS byte of given data
+	rxData = (spiTransferByte((data>>8) & 0x00FF))<<8;
+	// send LS byte of given data
+	rxData |= (spiTransferByte(data & 0x00FF));
+
+	// return the received data
+	return rxData;
+}