/* USART Wait for Transmit Data Buffer Empty. 
Blocks until the transmit data buffer becomes empty and is ready to accept the next data word. */
void usart_wait_send_ready(uint32_t usart)
/* USART Wait for Transmit Data Buffer Empty. 
Blocks until the transmit data buffer becomes empty and is ready to accept the next data word. */
void usart_wait_send_ready(uint32_t usart)
{
	while ((USART_ISR(usart) & USART_ISR_TXE) == 0);
}