mirror of https://github.com/ArduPilot/ardupilot
94 lines
2.3 KiB
C++
94 lines
2.3 KiB
C++
/*
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* SPI3.cpp - SPI library using UART3 for Ardupilot Mega
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* Code by Randy Mackay, DIYDrones.com
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* but mostly based on standard Arduino SPI class by Cristian Maglie <c.maglie@bug.st>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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*/
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#include "pins_arduino.h"
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#include "SPI3.h"
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SPI3Class SPI3;
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bool SPI3Class::_initialised = false;
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void SPI3Class::begin() {
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// check if begin has been run already
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if( _initialised ) {
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return;
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}
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// Set direction register for SCK and MOSI pin.
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pinMode(SPI3_SCK, OUTPUT);
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pinMode(SPI3_MOSI, OUTPUT);
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pinMode(SPI3_MISO, INPUT);
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// Setup Serial Port3 in SPI mode (MSPI), Mode 0, Clock: 8Mhz
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UBRR3 = 0;
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DDRJ |= (1<<PJ2); // SPI clock XCK3 (PJ2) as output. This enable SPI Master mode
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// put UART3 into SPI master mode, default mode and LSB bit order
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UCSR3C = SPI3_USART_SPI_MASTER | SPI3_DEFAULT_MODE;
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// Enable receiver and transmitter.
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UCSR3B = (1<<RXEN3)|(1<<TXEN3);
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// Set Baud rate
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UBRR3 = SPI3_DEFAULT_SPEED; // SPI running at 2Mhz by default
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// initialisation complete
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_initialised = true;
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}
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// end - switch UART3 back to asyncronous UART
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// Note: this is untested
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void SPI3Class::end() {
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uint8_t temp = UCSR3C;
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// put UART3 into ASync UART mode
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temp = (temp & ~SPI3_USART_MASK) | SPI3_USART_ASYNC_UART;
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UCSR3C = temp;
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// reinitialisation will be required
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_initialised = false;
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}
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uint8_t SPI3Class::transfer(uint8_t data) {
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/* Wait for empty transmit buffer */
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while ( !( UCSR3A & (1<<UDRE3)) ) ;
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/* Put data into buffer, sends the data */
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UDR3 = data;
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/* Wait for data to be received */
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while ( !(UCSR3A & (1<<RXC3)) ) ;
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/* Get and return received data from buffer */
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return UDR3;
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}
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void SPI3Class::setBitOrder(uint8_t bitOrder)
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{
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if(bitOrder == SPI3_LSBFIRST) {
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UCSR3C |= _BV(2);
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} else {
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UCSR3C &= ~(_BV(2));
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}
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}
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void SPI3Class::setDataMode(uint8_t mode)
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{
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UCSR3C = (UCSR3C & ~SPI3_MODE_MASK) | mode;
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}
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void SPI3Class::setSpeed(uint8_t rate)
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{
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UBRR3 = rate;
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}
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