SAML21走起6：TC0 定时器

In this use case, the TC will be used as a timer, to generate overflow and compare match callbacks.



In the callbacks the on-board LED is toggled.



The TC module will be set up as follows:



•GCLK generator 1 (GCLK 32K) clock source

•16-bit resolution on the counter

•Prescaler is divided by 64

•GCLK reload action

•Count upward

•Don't run in standby

•No waveform outputs

•No capture enabled

•Don't perform one-shot operations

•No event input enabled

•No event action

•No event generation enabled

•Counter starts on 0

•Counter top set to 2000 (about 4s) and generate overflow callback

•Channel 0 is set to compare and match value 900 and generate callback

•Channel 1 is set to compare and match value 930 and generate callback

#include <asf.h>

#define CONF_TC_MODULE TC3



struct tc_module tc_instance;

void tc_callback_to_toggle_led(struct tc_module *const module_inst);

void configure_tc(void);

void configure_tc_callbacks(void);



void tc_callback_to_toggle_led( struct tc_module *const module_inst)

{ port_pin_toggle_output_level(LED0_PIN);}

void configure_tc(void)

{ struct tc_config config_tc;

tc_get_config_defaults(&config_tc);

config_tc.counter_size = TC_COUNTER_SIZE_8BIT;

config_tc.clock_source = GCLK_GENERATOR_1;

config_tc.clock_prescaler = TC_CLOCK_PRESCALER_DIV1024;

config_tc.counter_8_bit.period = 100;

config_tc.counter_8_bit.compare_capture_channel[0] = 50;

config_tc.counter_8_bit.compare_capture_channel[1] = 54;

tc_init(&tc_instance, CONF_TC_MODULE, &config_tc);

tc_enable(&tc_instance);}

void configure_tc_callbacks(void)

{ tc_register_callback(&tc_instance, tc_callback_to_toggle_led, TC_CALLBACK_OVERFLOW);

tc_register_callback(&tc_instance, tc_callback_to_toggle_led, TC_CALLBACK_CC_CHANNEL0);

tc_register_callback(&tc_instance, tc_callback_to_toggle_led, TC_CALLBACK_CC_CHANNEL1);

tc_enable_callback(&tc_instance, TC_CALLBACK_OVERFLOW);

tc_enable_callback(&tc_instance, TC_CALLBACK_CC_CHANNEL0);

tc_enable_callback(&tc_instance, TC_CALLBACK_CC_CHANNEL1);}



int main (void)

{

system_init();

configure_tc(); 

configure_tc_callbacks();

system_interrupt_enable_global();



while (1)



{

}

}