Correct an issue where write could send data out of order.

collin80 · collin80 · commit 76280e87789c · 2014-12-31T08:42:26.000-05:00
diff --git a/hardware/arduino/sam/cores/arduino/UARTClass.cpp b/hardware/arduino/sam/cores/arduino/UARTClass.cpp
@@ -141,7 +141,7 @@ void UARTClass::flush( void )
 
 size_t UARTClass::write( const uint8_t uc_data )
 {
-  if ((_pUart->UART_SR & UART_SR_TXRDY) != UART_SR_TXRDY) //is the hardware currently busy?
+  if (((_pUart->UART_SR & UART_SR_TXRDY) != UART_SR_TXRDY) | (_tx_buffer->_iTail != _tx_buffer->_iHead)) //is the hardware currently busy?
   {
 	  //if busy we buffer
 	  unsigned int l = (_tx_buffer->_iHead + 1) % SERIAL_BUFFER_SIZE;

Original file line number	Diff line number	Diff line change
`@@ -141,7 +141,7 @@ void UARTClass::flush( void )`
`141`	`141`
`142`	`142`	`size_t UARTClass::write( const uint8_t uc_data )`
`143`	`143`	`{`
`144`		`- if ((_pUart->UART_SR & UART_SR_TXRDY) != UART_SR_TXRDY) //is the hardware currently busy?`
	`144`	`+ if (((_pUart->UART_SR & UART_SR_TXRDY) != UART_SR_TXRDY) \| (_tx_buffer->_iTail != _tx_buffer->_iHead)) //is the hardware currently busy?`
`145`	`145`	`{`
`146`	`146`	`//if busy we buffer`
`147`	`147`	`unsigned int l = (_tx_buffer->_iHead + 1) % SERIAL_BUFFER_SIZE;`