260 lines
9.2 KiB
C
260 lines
9.2 KiB
C
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/* ----------------------------------------------------------------------------
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* ATMEL Microcontroller Software Support
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* ----------------------------------------------------------------------------
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* Copyright (c) 2008, Atmel Corporation
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*
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* - Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the disclaimer below.
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*
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* Atmel's name may not be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* DISCLAIMER: THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
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* DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
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* OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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* ----------------------------------------------------------------------------
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*/
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//------------------------------------------------------------------------------
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// Headers
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//------------------------------------------------------------------------------
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#include "usart.h"
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#include <utility/trace.h>
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//------------------------------------------------------------------------------
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// Exported functions
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//------------------------------------------------------------------------------
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//------------------------------------------------------------------------------
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/// Configures an USART peripheral with the specified parameters.
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/// \param usart Pointer to the USART peripheral to configure.
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/// \param mode Desired value for the USART mode register (see the datasheet).
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/// \param baudrate Baudrate at which the USART should operate (in Hz).
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/// \param masterClock Frequency of the system master clock (in Hz).
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//------------------------------------------------------------------------------
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void USART_Configure(AT91S_USART *usart,
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unsigned int mode,
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unsigned int baudrate,
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unsigned int masterClock)
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{
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// Reset and disable receiver & transmitter
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usart->US_CR = AT91C_US_RSTRX | AT91C_US_RSTTX
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| AT91C_US_RXDIS | AT91C_US_TXDIS;
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// Configure mode
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usart->US_MR = mode;
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// Configure baudrate
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// Asynchronous, no oversampling
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if (((mode & AT91C_US_SYNC) == 0)
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&& ((mode & AT91C_US_OVER) == 0)) {
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usart->US_BRGR = (masterClock / baudrate) / 16;
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}
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// TODO other modes
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}
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//------------------------------------------------------------------------------
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/// Enables or disables the transmitter of an USART peripheral.
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/// \param usart Pointer to an USART peripheral
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/// \param enabled If true, the transmitter is enabled; otherwise it is
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/// disabled.
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//------------------------------------------------------------------------------
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void USART_SetTransmitterEnabled(AT91S_USART *usart,
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unsigned char enabled)
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{
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if (enabled) {
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usart->US_CR = AT91C_US_TXEN;
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}
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else {
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usart->US_CR = AT91C_US_TXDIS;
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}
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}
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//------------------------------------------------------------------------------
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/// Enables or disables the receiver of an USART peripheral
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/// \param usart Pointer to an USART peripheral
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/// \param enabled If true, the receiver is enabled; otherwise it is disabled.
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//------------------------------------------------------------------------------
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void USART_SetReceiverEnabled(AT91S_USART *usart,
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unsigned char enabled)
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{
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if (enabled) {
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usart->US_CR = AT91C_US_RXEN;
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}
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else {
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usart->US_CR = AT91C_US_RXDIS;
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}
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}
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//------------------------------------------------------------------------------
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/// Sends one packet of data through the specified USART peripheral. This
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/// function operates synchronously, so it only returns when the data has been
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/// actually sent.
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/// \param usart Pointer to an USART peripheral.
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/// \param data Data to send including 9nth bit and sync field if necessary (in
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/// the same format as the US_THR register in the datasheet).
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/// \param timeOut Time out value (0 = no timeout).
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//------------------------------------------------------------------------------
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void USART_Write(
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AT91S_USART *usart,
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unsigned short data,
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volatile unsigned int timeOut)
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{
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if (timeOut == 0) {
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while ((usart->US_CSR & AT91C_US_TXEMPTY) == 0);
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}
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else {
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while ((usart->US_CSR & AT91C_US_TXEMPTY) == 0) {
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if (timeOut == 0) {
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trace_LOG(trace_ERROR, "-E- USART_Write: Timed out.\n\r");
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return;
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}
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timeOut--;
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}
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}
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usart->US_THR = data;
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}
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//------------------------------------------------------------------------------
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/// Sends the contents of a data buffer through the specified USART peripheral.
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/// This function returns immediately (1 if the buffer has been queued, 0
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/// otherwise); poll the ENDTX and TXBUFE bits of the USART status register
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/// to check for the transfer completion.
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/// \param usart Pointer to an USART peripheral.
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/// \param buffer Pointer to the data buffer to send.
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/// \param size Size of the data buffer (in bytes).
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//------------------------------------------------------------------------------
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unsigned char USART_WriteBuffer(
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AT91S_USART *usart,
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void *buffer,
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unsigned int size)
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{
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// Check if the first PDC bank is free
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if ((usart->US_TCR == 0) && (usart->US_TNCR == 0)) {
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usart->US_TPR = (unsigned int) buffer;
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usart->US_TCR = size;
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usart->US_PTCR = AT91C_PDC_TXTEN;
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return 1;
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}
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// Check if the second PDC bank is free
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else if (usart->US_TNCR == 0) {
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usart->US_TNPR = (unsigned int) buffer;
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usart->US_TNCR = size;
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return 1;
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}
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else {
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return 0;
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}
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}
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//------------------------------------------------------------------------------
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/// Reads and return a packet of data on the specified USART peripheral. This
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/// function operates asynchronously, so it waits until some data has been
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/// received.
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/// \param usart Pointer to an USART peripheral.
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/// \param timeOut Time out value (0 -> no timeout).
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//------------------------------------------------------------------------------
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unsigned short USART_Read(
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AT91S_USART *usart,
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volatile unsigned int timeOut)
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{
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if (timeOut == 0) {
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while ((usart->US_CSR & AT91C_US_RXRDY) == 0);
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}
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else {
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while ((usart->US_CSR & AT91C_US_RXRDY) == 0) {
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if (timeOut == 0) {
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trace_LOG(trace_ERROR, "-E- USART_Read: Timed out.\n\r");
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return 0;
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}
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timeOut--;
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}
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}
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return usart->US_RHR;
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}
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//------------------------------------------------------------------------------
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/// Reads data from an USART peripheral, filling the provided buffer until it
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/// becomes full. This function returns immediately with 1 if the buffer has
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/// been queued for transmission; otherwise 0.
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/// \param usart Pointer to an USART peripheral.
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/// \param buffer Pointer to the buffer where the received data will be stored.
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/// \param size Size of the data buffer (in bytes).
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//------------------------------------------------------------------------------
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unsigned char USART_ReadBuffer(AT91S_USART *usart,
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void *buffer,
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unsigned int size)
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{
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// Check if the first PDC bank is free
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if ((usart->US_RCR == 0) && (usart->US_RNCR == 0)) {
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usart->US_RPR = (unsigned int) buffer;
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usart->US_RCR = size;
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usart->US_PTCR = AT91C_PDC_RXTEN;
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return 1;
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}
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// Check if the second PDC bank is free
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else if (usart->US_RNCR == 0) {
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usart->US_RNPR = (unsigned int) buffer;
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usart->US_RNCR = size;
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return 1;
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}
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else {
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return 0;
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}
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}
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//------------------------------------------------------------------------------
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/// Returns 1 if some data has been received and can be read from an USART;
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/// otherwise returns 0.
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/// \param usart Pointer to an AT91S_USART instance.
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//------------------------------------------------------------------------------
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unsigned char USART_IsDataAvailable(AT91S_USART *usart)
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{
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if ((usart->US_CSR & AT91C_US_RXRDY) != 0) {
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return 1;
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}
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else {
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return 0;
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}
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}
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