diff options
Diffstat (limited to 'libraries/Robot_Control/SPI.cpp')
-rw-r--r-- | libraries/Robot_Control/SPI.cpp | 66 |
1 files changed, 66 insertions, 0 deletions
diff --git a/libraries/Robot_Control/SPI.cpp b/libraries/Robot_Control/SPI.cpp new file mode 100644 index 0000000..5e48073 --- /dev/null +++ b/libraries/Robot_Control/SPI.cpp @@ -0,0 +1,66 @@ +/* + * Copyright (c) 2010 by Cristian Maglie <c.maglie@bug.st> + * SPI Master library for arduino. + * + * This file is free software; you can redistribute it and/or modify + * it under the terms of either the GNU General Public License version 2 + * or the GNU Lesser General Public License version 2.1, both as + * published by the Free Software Foundation. + */ + +#include "pins_arduino.h" +#include "SPI.h" + +SPIClass SPI; + +void SPIClass::begin() { + + // Set SS to high so a connected chip will be "deselected" by default + digitalWrite(SS, HIGH); + + // When the SS pin is set as OUTPUT, it can be used as + // a general purpose output port (it doesn't influence + // SPI operations). + pinMode(SS, OUTPUT); + + // Warning: if the SS pin ever becomes a LOW INPUT then SPI + // automatically switches to Slave, so the data direction of + // the SS pin MUST be kept as OUTPUT. + SPCR |= _BV(MSTR); + SPCR |= _BV(SPE); + + // Set direction register for SCK and MOSI pin. + // MISO pin automatically overrides to INPUT. + // By doing this AFTER enabling SPI, we avoid accidentally + // clocking in a single bit since the lines go directly + // from "input" to SPI control. + // http://code.google.com/p/arduino/issues/detail?id=888 + pinMode(SCK, OUTPUT); + pinMode(MOSI, OUTPUT); +} + + +void SPIClass::end() { + SPCR &= ~_BV(SPE); +} + +void SPIClass::setBitOrder(uint8_t bitOrder) +{ + if(bitOrder == LSBFIRST) { + SPCR |= _BV(DORD); + } else { + SPCR &= ~(_BV(DORD)); + } +} + +void SPIClass::setDataMode(uint8_t mode) +{ + SPCR = (SPCR & ~SPI_MODE_MASK) | mode; +} + +void SPIClass::setClockDivider(uint8_t rate) +{ + SPCR = (SPCR & ~SPI_CLOCK_MASK) | (rate & SPI_CLOCK_MASK); + SPSR = (SPSR & ~SPI_2XCLOCK_MASK) | ((rate >> 2) & SPI_2XCLOCK_MASK); +} + |