EBIKE-FreeRTOS/Common/drivers/Atmel/at91lib/peripherals/pwmc/pwmc.c

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2024-04-14 18:38:39 +08:00
/* ----------------------------------------------------------------------------
* ATMEL Microcontroller Software Support
* ----------------------------------------------------------------------------
* Copyright (c) 2008, 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.
* ----------------------------------------------------------------------------
*/
//------------------------------------------------------------------------------
// Headers
//------------------------------------------------------------------------------
#include "pwmc.h"
#include <board.h>
#include <utility/assert.h>
#include <utility/trace.h>
//------------------------------------------------------------------------------
// Local functions
//------------------------------------------------------------------------------
//------------------------------------------------------------------------------
/// Finds a prescaler/divisor couple to generate the desired frequency from
/// MCK.
/// Returns the value to enter in PWMC_MR or 0 if the configuration cannot be
/// met.
/// \param frequency Desired frequency in Hz.
/// \param mck Master clock frequency in Hz.
//------------------------------------------------------------------------------
static unsigned short FindClockConfiguration(
unsigned int frequency,
unsigned int mck)
{
unsigned int divisors[11] = {1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024};
unsigned char divisor = 0;
unsigned int prescaler;
SANITY_CHECK(frequency < mck);
// Find prescaler and divisor values
prescaler = (mck / divisors[divisor]) / frequency;
while ((prescaler > 255) && (divisor < 11)) {
divisor++;
prescaler = (mck / divisors[divisor]) / frequency;
}
// Return result
if (divisor < 11) {
trace_LOG(trace_DEBUG, "-D- Found divisor=%u and prescaler=%u for freq=%uHz\n\r",
divisors[divisor], prescaler, frequency);
return prescaler | (divisor << 8);
}
else {
return 0;
}
}
//------------------------------------------------------------------------------
// Global functions
//------------------------------------------------------------------------------
//------------------------------------------------------------------------------
/// Configures PWM a channel with the given parameters.
/// The PWM controller must have been clocked in the PMC prior to calling this
/// function.
/// \param channel Channel number.
/// \param prescaler Channel prescaler.
/// \param alignment Channel alignment.
/// \param polarity Channel polarity.
//------------------------------------------------------------------------------
void PWMC_ConfigureChannel(
unsigned char channel,
unsigned int prescaler,
unsigned int alignment,
unsigned int polarity)
{
SANITY_CHECK(prescaler < AT91C_PWMC_CPRE_MCKB);
SANITY_CHECK((alignment & ~AT91C_PWMC_CALG) == 0);
SANITY_CHECK((polarity & ~AT91C_PWMC_CPOL) == 0);
// Disable channel
AT91C_BASE_PWMC->PWMC_DIS = 1 << channel;
// Configure channel
AT91C_BASE_PWMC->PWMC_CH[channel].PWMC_CMR = prescaler | alignment | polarity;
}
//------------------------------------------------------------------------------
/// Configures PWM clocks A & B to run at the given frequencies. This function
/// finds the best MCK divisor and prescaler values automatically.
/// \param clka Desired clock A frequency (0 if not used).
/// \param clkb Desired clock B frequency (0 if not used).
/// \param mck Master clock frequency.
//------------------------------------------------------------------------------
void PWMC_ConfigureClocks(unsigned int clka, unsigned int clkb, unsigned int mck)
{
unsigned int mode = 0;
unsigned int result;
// Clock A
if (clka != 0) {
result = FindClockConfiguration(clka, mck);
ASSERT(result != 0, "-F- Could not generate the desired PWM frequency (%uHz)\n\r", clka);
mode |= result;
}
// Clock B
if (clkb != 0) {
result = FindClockConfiguration(clkb, mck);
ASSERT(result != 0, "-F- Could not generate the desired PWM frequency (%uHz)\n\r", clkb);
mode |= (result << 16);
}
// Configure clocks
trace_LOG(trace_DEBUG, "-D- Setting PWMC_MR = 0x%08X\n\r", mode);
AT91C_BASE_PWMC->PWMC_MR = mode;
}
//------------------------------------------------------------------------------
/// Sets the period value used by a PWM channel. This function writes directly
/// to the CPRD register if the channel is disabled; otherwise, it uses the
/// update register CUPD.
/// \param channel Channel number.
/// \param period Period value.
//------------------------------------------------------------------------------
void PWMC_SetPeriod(unsigned char channel, unsigned short period)
{
// If channel is disabled, write to CPRD
if ((AT91C_BASE_PWMC->PWMC_SR & (1 << channel)) == 0) {
AT91C_BASE_PWMC->PWMC_CH[channel].PWMC_CPRDR = period;
}
// Otherwise use update register
else {
AT91C_BASE_PWMC->PWMC_CH[channel].PWMC_CMR |= AT91C_PWMC_CPD;
AT91C_BASE_PWMC->PWMC_CH[channel].PWMC_CUPDR = period;
}
}
//------------------------------------------------------------------------------
/// Sets the duty cycle used by a PWM channel. This function writes directly to
/// the CDTY register if the channel is disabled; otherwise it uses the
/// update register CUPD.
/// Note that the duty cycle must always be inferior or equal to the channel
/// period.
/// \param channel Channel number.
/// \param duty Duty cycle value.
//------------------------------------------------------------------------------
void PWMC_SetDutyCycle(unsigned char channel, unsigned short duty)
{
SANITY_CHECK(duty <= AT91C_BASE_PWMC->PWMC_CH[channel].PWMC_CPRDR);
// SAM7S errata
#if defined(at91sam7s16) || defined(at91sam7s161) || defined(at91sam7s32) \
|| defined(at91sam7s321) || defined(at91sam7s64) || defined(at91sam7s128) \
|| defined(at91sam7s256) || defined(at91sam7s512)
ASSERT(duty > 0, "-F- Duty cycle value 0 is not permitted on SAM7S chips.\n\r");
ASSERT((duty > 1) || (AT91C_BASE_PWMC->PWMC_CH[channel].PWMC_CMR & AT91C_PWMC_CALG),
"-F- Duty cycle value 1 is not permitted in left-aligned mode on SAM7S chips.\n\r");
#endif
// If channel is disabled, write to CDTY
if ((AT91C_BASE_PWMC->PWMC_SR & (1 << channel)) == 0) {
AT91C_BASE_PWMC->PWMC_CH[channel].PWMC_CDTYR = duty;
}
// Otherwise use update register
else {
AT91C_BASE_PWMC->PWMC_CH[channel].PWMC_CMR &= ~AT91C_PWMC_CPD;
AT91C_BASE_PWMC->PWMC_CH[channel].PWMC_CUPDR = duty;
}
}
//------------------------------------------------------------------------------
/// Enables the given PWM channel. This does NOT enable the corresponding pin;
/// this must be done in the user code.
/// \param channel Channel number.
//------------------------------------------------------------------------------
void PWMC_EnableChannel(unsigned char channel)
{
AT91C_BASE_PWMC->PWMC_ENA = 1 << channel;
}
//------------------------------------------------------------------------------
/// Disables the given PWM channel.
/// \param channel Channel number.
//------------------------------------------------------------------------------
void PWMC_DisableChannel(unsigned char channel)
{
AT91C_BASE_PWMC->PWMC_DIS = 1 << channel;
}
//------------------------------------------------------------------------------
/// Enables the period interrupt for the given PWM channel.
/// \param channel Channel number.
//------------------------------------------------------------------------------
void PWMC_EnableChannelIt(unsigned char channel)
{
AT91C_BASE_PWMC->PWMC_IER = 1 << channel;
}
//------------------------------------------------------------------------------
/// Disables the period interrupt for the given PWM channel.
/// \param channel Channel number.
//------------------------------------------------------------------------------
void PWMC_DisableChannelIt(unsigned char channel)
{
AT91C_BASE_PWMC->PWMC_IDR = 1 << channel;
}