/* ---------------------------------------------------------------------------- | |
* SAM Software Package License | |
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* Copyright (c) 2015, Atmel Corporation | |
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*/ | |
/** \addtogroup tc_module | |
* \section Purpose | |
* The TC driver provides the Interface to configure the Timer Counter (TC). | |
* | |
* \section Usage | |
* <ul> | |
* <li> Optionally, use tc_find_mck_divisor() to let the program find the best | |
* TCCLKS field value automatically.</li> | |
* <li> Configure a Timer Counter in the desired mode using tc_configure().</li> | |
* <li> Start or stop the timer clock using tc_start() and tc_stop().</li> | |
* </li> | |
* </ul> | |
* For more accurate information, please look at the TC section of the Datasheet. | |
* | |
* Related files :\n | |
* \ref tc.c\n | |
* \ref tc.h.\n | |
*/ | |
/** | |
* \file | |
* | |
* \section Purpose | |
* | |
* Interface for configuring and using Timer Counter (TC) peripherals. | |
* | |
* \section Usage | |
* -# Optionally, use tc_find_mck_divisor() to let the program find the best | |
* TCCLKS field value automatically. | |
* -# Configure a Timer Counter in the desired mode using tc_configure(). | |
* -# Start or stop the timer clock using tc_start() and tc_stop(). | |
*/ | |
/** | |
* \file | |
* | |
* Implementation of Timer Counter (TC). | |
* | |
*/ | |
/*------------------------------------------------------------------------------ | |
* Headers | |
*------------------------------------------------------------------------------*/ | |
#include "chip.h" | |
#include "peripherals/tc.h" | |
#include "peripherals/pmc.h" | |
#include <assert.h> | |
/*------------------------------------------------------------------------------ | |
* Global functions | |
*------------------------------------------------------------------------------*/ | |
/** | |
* \brief Configures a Timer Counter Channel | |
* | |
* Configures a Timer Counter to operate in the given mode. Timer is stopped | |
* after configuration and must be restarted with tc_start(). All the | |
* interrupts of the timer are also disabled. | |
* | |
* \param pTc Pointer to a Tc instance. | |
* \param channel Channel number. | |
* \param mode Operating mode (TC_CMR value). | |
*/ | |
void tc_configure(Tc * pTc, uint32_t channel, uint32_t mode) | |
{ | |
volatile TcChannel *pTcCh; | |
assert(channel < | |
(sizeof (pTc->TC_CHANNEL) / sizeof (pTc->TC_CHANNEL[0]))); | |
pTcCh = pTc->TC_CHANNEL + channel; | |
/* Disable TC clock */ | |
pTcCh->TC_CCR = TC_CCR_CLKDIS; | |
/* Disable interrupts */ | |
pTcCh->TC_IDR = 0xFFFFFFFF; | |
/* Clear status register */ | |
pTcCh->TC_SR; | |
/* Set mode */ | |
pTcCh->TC_CMR = mode; | |
} | |
/** | |
* \brief Reset and Start the TC Channel | |
* | |
* Enables the timer clock and performs a software reset to start the counting. | |
* | |
* \param pTc Pointer to a Tc instance. | |
* \param channel Channel number. | |
*/ | |
void tc_start(Tc * pTc, uint32_t channel) | |
{ | |
volatile TcChannel *pTcCh; | |
assert(channel < | |
(sizeof (pTc->TC_CHANNEL) / sizeof (pTc->TC_CHANNEL[0]))); | |
pTcCh = pTc->TC_CHANNEL + channel; | |
pTcCh->TC_CCR = TC_CCR_CLKEN | TC_CCR_SWTRG; | |
pTcCh->TC_IER = TC_IER_COVFS; | |
} | |
/** | |
* \brief Stop TC Channel | |
* | |
* Disables the timer clock, stopping the counting. | |
* | |
* \param pTc Pointer to a Tc instance. | |
* \param channel Channel number. | |
*/ | |
void tc_stop(Tc * pTc, uint32_t channel) | |
{ | |
volatile TcChannel *pTcCh; | |
assert(channel < | |
(sizeof (pTc->TC_CHANNEL) / sizeof (pTc->TC_CHANNEL[0]))); | |
pTcCh = pTc->TC_CHANNEL + channel; | |
pTcCh->TC_CCR = TC_CCR_CLKDIS; | |
pTcCh->TC_IDR = TC_IER_COVFS; | |
} | |
/** | |
* \brief Enables TC channel interrupts | |
* | |
* \param tc Pointer to Tc instance | |
* \param channel Channel number | |
* \param mask mask of interrupts to enable | |
*/ | |
void tc_enable_it(Tc* tc, uint32_t channel, uint32_t mask) | |
{ | |
assert(channel < (sizeof (tc->TC_CHANNEL) / sizeof (tc->TC_CHANNEL[0]))); | |
tc->TC_CHANNEL[channel].TC_IER = mask; | |
} | |
/** | |
* \brief Find best MCK divisor | |
* | |
* Finds the best MCK divisor given the timer frequency and MCK. The result | |
* is guaranteed to satisfy the following equation: | |
* \code | |
* (MCK / (DIV * 65536)) <= freq <= (MCK / DIV) | |
* \endcode | |
* with DIV being the highest possible value. | |
* | |
* \param freq Desired timer freq. | |
* \param div Divisor value. | |
* \param tc_clks TCCLKS field value for divisor. | |
* | |
* \return 1 if a proper divisor has been found, otherwise 0. | |
*/ | |
uint32_t tc_find_mck_divisor (uint32_t freq, uint32_t * div, | |
uint32_t * tc_clks) | |
{ | |
const uint32_t periph_clock = pmc_get_peripheral_clock(ID_TC0); | |
const uint32_t available_freqs[5] = {periph_clock >> 1, periph_clock >> 3, periph_clock >> 5, periph_clock >> 7, 32768}; | |
int i = 0; | |
for (i = 0; i < 5; ++i) | |
{ | |
uint32_t tmp = freq << 1; | |
if (tmp > available_freqs[i]) | |
break; | |
} | |
i = (i == 5 ? i-1 : i); | |
/* Store results */ | |
if (div) { | |
*div = periph_clock / available_freqs[i]; | |
} | |
if (tc_clks) { | |
*tc_clks = i; | |
} | |
return 1; | |
} | |
uint32_t tc_get_status(Tc* tc, uint32_t channel_num) | |
{ | |
return tc->TC_CHANNEL[channel_num].TC_SR; | |
} | |
void tc_trigger_on_freq(Tc* tc, uint32_t channel_num, uint32_t freq) | |
{ | |
uint32_t div = 0; | |
uint32_t tcclks = 0; | |
uint32_t tc_id = get_tc_id_from_addr(tc); | |
TcChannel* channel = &tc->TC_CHANNEL[channel_num]; | |
tc_find_mck_divisor(freq, &div, &tcclks); | |
tc_configure(tc, channel_num, tcclks | TC_CMR_CPCTRG); | |
channel->TC_RC = (pmc_get_peripheral_clock(tc_id) / div) / freq; | |
} |