int main(void)
{
//! [setup_init]
struct tc_module tc_instance;
struct events_resource example_event;
struct events_hook hook;
system_init();
system_interrupt_enable_global();
configure_event_channel(&example_event);
configure_event_user(&example_event);
configure_event_interrupt(&example_event, &hook);
configure_tc(&tc_instance);
//! [setup_init]
//! [main]
//! [main_1]
while (events_is_busy(&example_event)) {
/* Wait for channel */
};
//! [main_1]
//! [main_2]
tc_start_counter(&tc_instance);
//! [main_2]
while (true) {
/* Nothing to do */
}
//! [main]
}
/*!
* @brief Implements a delay of the length of the argument in
econds
*
* @param[in] NULL
*
* @param[out] NULL
*
* @return NULL
*
*/
void tc4_wait_for_msec (uint32_t msec)
{
/* Set the compare value */
tc_set_compare_value(&tc4_instance, TC_COMPARE_CAPTURE_CHANNEL_0, (msec *500));
/* start counting */
tc_start_counter(&tc4_instance);
/* delay until required time is elapsed */
while (!tc4_callback_flag);
/* stop the counter */
tc_stop_counter(&tc4_instance);
/* reset the interrupt flag */
tc4_callback_flag = false;
}
/**
* \internal
* \brief Test basic functionality.
*
* This test tests the basic functionality for the TC. It tests the following functions:
* - tc_get_count_value()
* - tc_stop_counter()
* - tc_set_count_value()
* - tc_start_counter()
*
* \param test Current test case.
*/
static void run_basic_functionality_test(const struct test_case *test)
{
test_assert_true(test,
tc_init_success == true,
"TC initialization failed, skipping test");
/* Setup TC0 */
tc_reset(&tc_test0_module);
tc_get_config_defaults(&tc_test0_config);
tc_init(&tc_test0_module, CONF_TEST_TC0, &tc_test0_config);
tc_enable(&tc_test0_module);
/* Test tc_get_count_value() */
uint32_t test_val0 = tc_get_count_value(&tc_test0_module);
test_assert_true(test,
test_val0 > 0,
"The tc_get_count_value() returned 0 expected larger value");
/* Test tc_stop_counter() */
tc_stop_counter(&tc_test0_module);
uint32_t test_val1 = tc_get_count_value(&tc_test0_module);
uint32_t test_val2 = tc_get_count_value(&tc_test0_module);
test_assert_true(test,
test_val1 == test_val2,
"The counter failed to stop");
/* Test tc_set_count_value() */
tc_set_count_value(&tc_test0_module, 0x00FF);
test_assert_true(test,
tc_get_count_value(&tc_test0_module) == 0x00FF,
"tc_set_count_value() have failed");
/* Test tc_start_counter() */
tc_start_counter(&tc_test0_module);
test_assert_true(test,
tc_get_count_value(&tc_test0_module) > 0x00FF,
"tc_get_count_value() have failed");
basic_functionality_test_passed = true;
}
/**
* \brief Configures the DAC in event triggered mode.
*
* Configures the DAC to use the module's default configuration, with output
* channel mode configured for event triggered conversions.
*
* \param dev_inst Pointer to the DAC module software instance to initialize
*/
static void configure_dac(struct dac_module *dac_module)
{
struct dac_config config;
struct dac_chan_config channel_config;
/* Get the DAC default configuration */
dac_get_config_defaults(&config);
/* Switch to GCLK generator 0 */
config.clock_source = GCLK_GENERATOR_0;
dac_init(dac_module, DAC, &config);
/* Get the default DAC channel config */
dac_chan_get_config_defaults(&channel_config);
/* Set the channel configuration, and enable it */
dac_chan_set_config(dac_module, DAC_CHANNEL_0, &channel_config);
dac_chan_enable(dac_module, DAC_CHANNEL_0);
/* Enable event triggered conversions */
struct dac_events events = { .on_event_start_conversion = true };
dac_enable_events(dac_module, &events);
dac_enable(dac_module);
}
/**
* \brief Configures the TC to generate output events at the sample frequency.
*
* Configures the TC in Frequency Generation mode, with an event output once
* each time the audio sample frequency period expires.
*
* \param dev_inst Pointer to the TC module software instance to initialize
*/
static void configure_tc(struct tc_module *tc_module)
{
struct tc_config config;
tc_get_config_defaults(&config);
config.clock_source = GCLK_GENERATOR_0;
config.wave_generation = TC_WAVE_GENERATION_MATCH_FREQ;
tc_init(tc_module, TC3, &config);
/* Enable periodic event output generation */
struct tc_events events = { .generate_event_on_overflow = true };
tc_enable_events(tc_module, &events);
/* Set the timer top value to alter the overflow frequency */
tc_set_top_value(tc_module,
system_gclk_gen_get_hz(GCLK_GENERATOR_0) / sample_rate);
tc_enable(tc_module);
}
/**
* \brief Configures the event system to link the sample timer to the DAC.
*
* Configures the event system, linking the TC module used for the audio sample
* rate timing to the DAC, so that a new conversion is triggered each time the
* DAC receives an event from the timer.
*/
static void configure_events(struct events_resource *event)
{
struct events_config config;
events_get_config_defaults(&config);
config.generator = EVSYS_ID_GEN_TC3_OVF;
config.path = EVENTS_PATH_ASYNCHRONOUS;
events_allocate(event, &config);
events_attach_user(event, EVSYS_ID_USER_DAC_START);
}
/**
* \brief Main application routine
*/
int main(void)
{
struct dac_module dac_module;
struct tc_module tc_module;
struct events_resource event;
/* Initialize all the system clocks, pm, gclk... */
system_init();
/* Enable the internal bandgap to use as reference to the DAC */
system_voltage_reference_enable(SYSTEM_VOLTAGE_REFERENCE_BANDGAP);
/* Module configuration */
configure_tc(&tc_module);
configure_dac(&dac_module);
configure_events(&event);
/* Start the sample trigger timer */
tc_start_counter(&tc_module);
while (true) {
while (port_pin_get_input_level(SW0_PIN) == SW0_INACTIVE) {
/* Wait for the button to be pressed */
}
port_pin_toggle_output_level(LED0_PIN);
for (uint32_t i = 0; i < number_of_samples; i++) {
dac_chan_write(&dac_module, DAC_CHANNEL_0, wav_samples[i]);
while (!(DAC->INTFLAG.reg & DAC_INTFLAG_EMPTY)) {
/* Wait for data buffer to be empty */
}
}
while (port_pin_get_input_level(SW0_PIN) == SW0_ACTIVE) {
/* Wait for the button to be depressed */
}
}
}
void platform_start_bus_timer(void *timer_handle, uint32_t ms)
{
tc_set_count_value(&bus_tc_instance, (0xFFFFFFFF - (timer_count_per_ms * ms)));
tc_start_counter(&bus_tc_instance);
}
/** Set up the measurement and comparison timer events.
* - Configure the reference timer to generate an event upon comparison
* match with channel 0.
* - Configure the measurement timer to trigger a capture when an event is
* received.
*/
static void setup_tc_events(void)
{
/* Enable incoming events on on measurement timer */
struct tc_events events_calib = { .on_event_perform_action = true };
tc_enable_events(&tc_calib, &events_calib);
/* Generate events from the reference timer on channel 0 compare match */
struct tc_events events_comp = { .generate_event_on_compare_channel[0] = true };
tc_enable_events(&tc_comp, &events_comp);
tc_enable(&tc_calib);
tc_enable(&tc_comp);
}
/** Set up the event system, linking the measurement and comparison timers so
* that events generated from the reference timer are linked to the measurement
* timer.
*/
static void setup_events(struct events_resource *event)
{
struct events_config config;
events_get_config_defaults(&config);
/* The event channel detects rising edges of the reference timer output
* event */
config.edge_detect = EVENTS_EDGE_DETECT_RISING;
config.path = EVENTS_PATH_SYNCHRONOUS;
config.generator = CONF_EVENT_GENERATOR_ID;
events_allocate(event, &config);
events_attach_user(event, CONF_EVENT_USED_ID);
}
/** Set up the USART for transmit-only communication at a fixed baud rate. */
static void setup_usart_channel(void)
{
struct usart_config cdc_uart_config;
usart_get_config_defaults(&cdc_uart_config);
/* Configure the USART settings and initialize the standard I/O library */
cdc_uart_config.mux_setting = EDBG_CDC_SERCOM_MUX_SETTING;
cdc_uart_config.pinmux_pad0 = EDBG_CDC_SERCOM_PINMUX_PAD0;
cdc_uart_config.pinmux_pad1 = EDBG_CDC_SERCOM_PINMUX_PAD1;
cdc_uart_config.pinmux_pad2 = EDBG_CDC_SERCOM_PINMUX_PAD2;
cdc_uart_config.pinmux_pad3 = EDBG_CDC_SERCOM_PINMUX_PAD3;
cdc_uart_config.baudrate = 115200;
stdio_serial_init(&usart_edbg, EDBG_CDC_MODULE, &cdc_uart_config);
usart_enable(&usart_edbg);
}
/** Set up the clock output pin so that the current system clock frequency can
* be monitored via an external frequency counter or oscilloscope. */
static void setup_clock_out_pin(void)
{
struct system_pinmux_config pin_mux;
system_pinmux_get_config_defaults(&pin_mux);
/* MUX out the system clock to a I/O pin of the device */
pin_mux.mux_position = CONF_CLOCK_PIN_MUX;
system_pinmux_pin_set_config(CONF_CLOCK_PIN_OUT, &pin_mux);
}
/** Retrieves the current system clock frequency, computed from the reference
* clock.
*
* \return Current system clock frequency in Hz.
*/
static uint32_t get_osc_frequency(void)
{
/* Clear any existing match status on the measurement timer */
tc_clear_status(&tc_comp, TC_STATUS_CHANNEL_0_MATCH);
/* Restart both measurement and reference timers */
tc_start_counter(&tc_calib);
tc_start_counter(&tc_comp);
/* Wait for the measurement timer to signal a compare match */
while (!(tc_get_status(&tc_comp) & TC_STATUS_CHANNEL_0_MATCH)) {
/* Wait for channel 0 match */
}
/* Compute the real clock frequency from the measurement timer count and
* reference count */
uint64_t tmp = tc_get_capture_value(&tc_calib, TC_COMPARE_CAPTURE_CHANNEL_0);
return ((tmp * REFERENCE_CLOCK_HZ) >> CALIBRATION_RESOLUTION);
}
int main(void)
{
struct events_resource event;
/* System initialization */
system_init();
delay_init();
/* Module initialization */
setup_tc_channels();
setup_tc_events();
setup_events(&event);
setup_clock_out_pin();
/* Init the variables with default calibration settings */
uint8_t frange_cal = SYSCTRL->OSC8M.bit.FRANGE;
uint8_t temp_cal = SYSCTRL->OSC8M.bit.CALIB >> TEMP_CAL_OFFSET;
uint8_t comm_cal = SYSCTRL->OSC8M.bit.CALIB & COMM_CAL_MAX;
/* Set the calibration test range */
uint8_t frange_cal_min = max((frange_cal - CONF_FRANGE_CAL), FRANGE_CAL_MIN);
uint8_t frange_cal_max = min((frange_cal + CONF_FRANGE_CAL), FRANGE_CAL_MAX);
uint8_t temp_cal_min = max((temp_cal - CONF_TEMP_CAL), TEMP_CAL_MIN);
uint8_t temp_cal_max = min((temp_cal + CONF_TEMP_CAL), TEMP_CAL_MAX);
/* Variables to track the previous and best calibration settings */
uint16_t comm_best = 0;
uint8_t frange_best = 0;
uint32_t freq_best = 0;
uint32_t freq_before = get_osc_frequency();
/* Run calibration loop */
for (frange_cal = frange_cal_min; frange_cal <= frange_cal_max; frange_cal++) {
for (temp_cal = temp_cal_min; temp_cal <= temp_cal_max; temp_cal++) {
for (comm_cal = COMM_CAL_MIN; comm_cal <= COMM_CAL_MAX; comm_cal++) {
/* Set the test calibration values */
system_clock_source_write_calibration(
SYSTEM_CLOCK_SOURCE_OSC8M, (temp_cal << 7) | comm_cal, frange_cal);
/* Wait for stabilization */
delay_cycles(1000);
/* Compute the deltas of the current and best system clock
* frequencies, save current settings if they are closer to the
* ideal frequency than the previous best values
*/
uint32_t freq_current = get_osc_frequency();
if (abs(freq_current - TARGET_FREQUENCY) < abs(freq_best - TARGET_FREQUENCY)) {
freq_best = freq_current;
comm_best = comm_cal;
frange_best = frange_cal;
port_pin_set_output_level(LED_0_PIN, LED_0_ACTIVE);
} else {
port_pin_set_output_level(LED_0_PIN, !LED_0_ACTIVE);
}
}
}
}
/* Set the found best calibration values */
system_clock_source_write_calibration(
SYSTEM_CLOCK_SOURCE_OSC8M, (temp_cal << 7) | comm_best, frange_best);
/* Setup USART module to output results */
setup_usart_channel();
/* Write previous and current frequency and new calibration settings to the
* USART
*/
printf("Freq Before: %lu\r\n", freq_before);
printf("Freq Best: %lu\r\n", freq_best);
printf("Freq Range: %u\r\n", frange_best);
printf("Calib Value: 0x%x\r\n", (temp_cal << 7) | comm_best);
/* Rapidly flash the board LED to signal the calibration completion */
while (1) {
port_pin_toggle_output_level(LED_0_PIN);
delay_ms(200);
}
}
/*!
* @brief Starts TC6 counter
*
* @param[in] NULL
*
* @param[out] NULL
*
* @return NULL
*
*/
void tc6_start_counter (void)
{
tc_set_count_value(&tc6_instance, TC6_COUNT_VALUE);
tc_start_counter(&tc6_instance);
}
/* Timer 0 Initialization */
void timer_init(void)
{
struct tc_config conf_tc;
struct tc_events conf_tc_events = {.generate_event_on_compare_channel[0] = 1};
tc_get_config_defaults(&conf_tc);
conf_tc.clock_source = GCLK_GENERATOR_0;
conf_tc.wave_generation = TC_WAVE_GENERATION_MATCH_FREQ;
conf_tc.counter_16_bit.compare_capture_channel[0] = 0xFFFF;
tc_init(&tc_inst, TC0, &conf_tc);
tc_enable_events(&tc_inst, &conf_tc_events);
tc_enable(&tc_inst);
tc_stop_counter(&tc_inst);
/* Enable TC0 match/capture channel 0 interrupt */
TC0->COUNT16.INTENSET.bit.MC0 = 1;
/* Enable TC0 module interrupt */
NVIC_EnableIRQ(TC0_IRQn);
}
/* DAC Initialization */
void dac_initialize(void)
{
struct dac_config conf_dac;
struct dac_events conf_dac_events = {.on_event_start_conversion = 1};
dac_get_config_defaults(&conf_dac);
conf_dac.clock_source = GCLK_GENERATOR_3;
conf_dac.reference = DAC_REFERENCE_INT1V;
dac_init(&dac_inst, DAC, &conf_dac);
dac_enable_events(&dac_inst, &conf_dac_events);
dac_enable(&dac_inst);
}
/* Event System Initialization */
void evsys_init(void)
{
struct events_resource conf_event_resource;
struct events_config conf_event;
events_get_config_defaults(&conf_event);
conf_event.edge_detect = EVENTS_EDGE_DETECT_NONE;
conf_event.path = EVENTS_PATH_ASYNCHRONOUS;
conf_event.generator = EVSYS_ID_GEN_TC0_MCX_0;
events_allocate(&conf_event_resource, &conf_event);
events_attach_user(&conf_event_resource, EVSYS_ID_USER_DAC_START);
}
/* Initialize the selected waveform buffer with output data */
void buffer_init(void)
{
#if WAVE_MODE==SINE_WAVE
for (i = 0; i < DEGREES_PER_CYCLE; i++) {
sine_wave_buf[i] = (uint16_t)(500 + (500*sin((double)i*DEGREE)));
}
#elif WAVE_MODE==SAW_TOOTH_WAVE
for (i = 0; i < 256; i++) {
sawtooth_wave_buf[i] = i*4;
}
#elif WAVE_MODE==TRIANGLE_WAVE
for (i = 0; i < 128; i++) {
triangle_wave_buf[i] = i*8;
}
for (i = 128; i < 256; i++) {
triangle_wave_buf[i] = 1023 - (i*8);
}
#endif
}
/* Main function */
int main(void)
{
system_init();
timer_init();
dac_initialize();
evsys_init();
buffer_init();
/* Set the TC0 compare value corresponding to specified frequency */
#if WAVE_MODE==SINE_WAVE
tc_set_compare_value(&tc_inst, 0, \
system_gclk_gen_get_hz(GCLK_GENERATOR_0)/(FREQUENCY*360));
#else
tc_set_compare_value(&tc_inst, 0, \
system_gclk_gen_get_hz(GCLK_GENERATOR_0)/(FREQUENCY*256));
#endif
/* Start TC0 timer */
tc_start_counter(&tc_inst);
/* Enable global interrupt */
system_interrupt_enable_global();
while (true) {
}
}
