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SPI3: add checks that SPI bus has been initialised to reduce possibility of interfering with UART3 on APM1

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This commit is contained in:
rmackay9 2012-10-18 19:17:24 +09:00
parent e0727e6d31
commit 0722d671d6
1 changed files with 27 additions and 8 deletions
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35
libraries/SPI3/SPI3.cpp
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@ -49,7 +49,12 @@ void SPI3Class::begin() {
// Note: this is untested
void SPI3Class::end() {
uint8_t temp = UCSR3C;
// check spi bus has been initialised
if( !_initialised ) {
return;
}
// put UART3 into ASync UART mode
temp = (temp & ~SPI3_USART_MASK) | SPI3_USART_ASYNC_UART;
UCSR3C = temp;
@ -59,6 +64,11 @@ void SPI3Class::end() {
}
uint8_t SPI3Class::transfer(uint8_t data) {
// check spi bus has been initialised
if( !_initialised ) {
return 0;
}
/* Wait for empty transmit buffer */
while ( !( UCSR3A & (1<<UDRE3)) ) ;
@ -74,20 +84,29 @@ uint8_t SPI3Class::transfer(uint8_t data) {
void SPI3Class::setBitOrder(uint8_t bitOrder)
{
if(bitOrder == SPI3_LSBFIRST) {
UCSR3C |= _BV(2);
} else {
UCSR3C &= ~(_BV(2));
}
// check spi bus has been initialised
if( !_initialised ) {
return;
}
if(bitOrder == SPI3_LSBFIRST) {
UCSR3C |= _BV(2);
} else {
UCSR3C &= ~(_BV(2));
}
}
void SPI3Class::setDataMode(uint8_t mode)
{
UCSR3C = (UCSR3C & ~SPI3_MODE_MASK) | mode;
if( _initialised ) {
UCSR3C = (UCSR3C & ~SPI3_MODE_MASK) | mode;
}
}
void SPI3Class::setSpeed(uint8_t rate)
{
UBRR3 = rate;
if( _initialised ) {
UBRR3 = rate;
}
}