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Arduino/hardware/sam/system/libsam/source/ssc.c

248 lines
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C

/* ----------------------------------------------------------------------------
* ATMEL Microcontroller Software Support
* ----------------------------------------------------------------------------
* Copyright (c) 2009, Atmel Corporation
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the disclaimer below.
*
* Atmel's name may not be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* DISCLAIMER: THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
* DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
* OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
* ----------------------------------------------------------------------------
*/
/** \addtogroup ssc_module Working with SSC
* The SSC driver provides the interface to configure and use the SSC
* peripheral.
*
* !Usage
*
* -# Enable the SSC interface pins.
* -# Configure the SSC to operate at a specific frequency by calling
* SSC_Configure(). This function enables the peripheral clock of the SSC,
* but not its PIOs.
* -# Configure the transmitter and/or the receiver using the
* SSC_ConfigureTransmitter() and SSC_ConfigureEmitter() functions.
* -# Enable the PIOs or the transmitter and/or the received.
* -# Enable the transmitter and/or the receiver using SSC_EnableTransmitter()
* and SSC_EnableReceiver()
* -# Send data through the transmitter using SSC_Write() and SSC_WriteBuffer()
* -# Receive data from the receiver using SSC_Read() and SSC_ReadBuffer()
* -# Disable the transmitter and/or the receiver using SSC_DisableTransmitter()
* and SSC_DisableReceiver()
*
* For more accurate information, please look at the RTC section of the
* Datasheet.
*
* Related files :\n
* \ref ssc.c\n
* \ref ssc.h.\n
*/
/*@{*/
/*@}*/
/**
* \file
*
* Implementation of Synchronous Serial (SSC) controller.
*
*/
/*----------------------------------------------------------------------------
* Headers
*----------------------------------------------------------------------------*/
#include "chip.h"
/*----------------------------------------------------------------------------
* Exported functions
*----------------------------------------------------------------------------*/
/**
* \brief Configures a SSC peripheral.If the divided clock is not used, the master
* clock frequency can be set to 0.
* \note The emitter and transmitter are disabled by this function.
* \param bitRate bit rate.
* \param masterClock master clock.
*/
void SSC_Configure(uint32_t bitRate, uint32_t masterClock)
{
/* Enable SSC peripheral clock */
PMC->PMC_PCER0 = 1 << ID_SSC;
/* Reset, disable receiver & transmitter */
SSC->SSC_CR = SSC_CR_RXDIS | SSC_CR_TXDIS | SSC_CR_SWRST;
SSC->SSC_PTCR = SSC_PTCR_RXTDIS | SSC_PTCR_TXTDIS;
/* Configure clock frequency */
if (bitRate != 0) {
SSC->SSC_CMR = masterClock / (2 * bitRate);
}
else {
SSC->SSC_CMR = 0;
}
}
/**
* \brief Configures the transmitter of a SSC peripheral.
* \param tcmr Transmit Clock Mode Register value.
* \param tfmr Transmit Frame Mode Register value.
*/
void SSC_ConfigureTransmitter(uint32_t tcmr, uint32_t tfmr)
{
SSC->SSC_TCMR = tcmr;
SSC->SSC_TFMR = tfmr;
}
/**
* \brief Configures the receiver of a SSC peripheral.
* \param rcmr Receive Clock Mode Register value.
* \param rfmr Receive Frame Mode Register value.
*/
void SSC_ConfigureReceiver(uint32_t rcmr, uint32_t rfmr)
{
SSC->SSC_RCMR = rcmr;
SSC->SSC_RFMR = rfmr;
}
/**
* \brief Enables the transmitter of a SSC peripheral.
*/
void SSC_EnableTransmitter(void)
{
SSC->SSC_CR = SSC_CR_TXEN;
}
/**
* \brief Disables the transmitter of a SSC peripheral.
*/
void SSC_DisableTransmitter(void)
{
SSC->SSC_CR = SSC_CR_TXDIS;
}
/**
* \brief Enables the receiver of a SSC peripheral.
*/
void SSC_EnableReceiver(void)
{
SSC->SSC_CR = SSC_CR_RXEN;
}
/**
* \brief Disables the receiver of a SSC peripheral.
*/
void SSC_DisableReceiver(void)
{
SSC->SSC_CR = SSC_CR_RXDIS;
}
/**
* \brief Enables one or more interrupt sources of a SSC peripheral.
* \param sources Bitwise OR of selected interrupt sources.
*/
void SSC_EnableInterrupts(uint32_t sources)
{
SSC->SSC_IER = sources;
}
/**
* \brief Disables one or more interrupt sources of a SSC peripheral.
* \param sources Bitwise OR of selected interrupt sources.
*/
void SSC_DisableInterrupts(uint32_t sources)
{
SSC->SSC_IDR = sources;
}
/**
* \brief Sends one data frame through a SSC peripheral. If another frame is currently
* being sent, this function waits for the previous transfer to complete.
* \param frame Data frame to send.
*/
void SSC_Write(uint32_t frame)
{
while ((SSC->SSC_SR & SSC_SR_TXRDY) == 0);
SSC->SSC_THR = frame;
}
/**
* \brief Waits until one frame is received on a SSC peripheral, and returns it.
*/
uint32_t SSC_Read(void)
{
while ((SSC->SSC_SR & SSC_SR_RXRDY) == 0);
return SSC->SSC_RHR;
}
/**
* \brief Sends the contents of a data buffer a SSC peripheral, using the PDC.
* \param buffer Data buffer to send.
* \param length Size of the data buffer.
* \return 1 if the buffer has been queued for transmission; otherwise returns 0.
*/
uint8_t SSC_WriteBuffer(void *buffer, uint32_t length)
{
/* Check if first bank is free*/
if (SSC->SSC_TCR == 0) {
SSC->SSC_TPR = (uint32_t) buffer;
SSC->SSC_TCR = length;
SSC->SSC_PTCR = SSC_PTCR_TXTEN;
return 1;
}
/* Check if second bank is free*/
else if (SSC->SSC_TNCR == 0) {
SSC->SSC_TNPR = (uint32_t) buffer;
SSC->SSC_TNCR = length;
return 1;
}
return 0;
}
/**
* \brief Reads data coming from a SSC peripheral receiver and stores it into the
* giving buffer with PDC.
* \param buffer ata buffer used for reception.
* \param length Size of the data buffer.
* \return 1 if the buffer has been queued for reception; otherwise returns 0.
*/
uint8_t SSC_ReadBuffer(void *buffer, uint32_t length)
{
/* Check if the first bank is free*/
if (SSC->SSC_RCR == 0) {
SSC->SSC_RPR = (uint32_t) buffer;
SSC->SSC_RCR = length;
SSC->SSC_PTCR = SSC_PTCR_RXTEN;
return 1;
}
/* Check if second bank is free*/
else if (SSC->SSC_RNCR == 0) {
SSC->SSC_RNPR = (uint32_t) buffer;
SSC->SSC_RNCR = length;
return 1;
}
return 0;
}