From 0722d671d6b0d67dda3f49d54874338d4a01ed97 Mon Sep 17 00:00:00 2001
From: rmackay9 <rmackay9@yahoo.com>
Date: Thu, 18 Oct 2012 19:17:24 +0900
Subject: [PATCH] SPI3: add checks that SPI bus has been initialised to reduce
possibility of interfering with UART3 on APM1
---
libraries/SPI3/SPI3.cpp | 35 +++++++++++++++++++++++++++--------
1 file changed, 27 insertions(+), 8 deletions(-)
diff --git a/libraries/SPI3/SPI3.cpp b/libraries/SPI3/SPI3.cpp
index 510046664..078abda81 100644
--- a/libraries/SPI3/SPI3.cpp
+++ b/libraries/SPI3/SPI3.cpp
@@ -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;
+ }
}
--
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