9.2. Code Examples

9.2.1. Print the elapsed time since the μC started

Following code prints out the time passed since the code started running on the microcontroller. Note that a sleep_ms() function is used in the setup() function to stall the μC at that line for 10 seconds. Make sure that you can connect to the μC during that time through Putty or Coolterm. Otherwise, you may miss the output.

#include <stdio.h>
#include <pico/stdlib.h>
#include <hardware/gpio.h>
#include <hardware/timer.h>

void setup()
{
    stdio_init_all();
    sleep_ms(10000);
}

void loop()
{
    // Get the lower 32-bit value of `CTR` register and print it
    uint32_t t32 = time_us_32();
    printf("%u\r\n", t32);
    sleep_ms(100);

    // Get complete 64-bit `CTR` value and print it
    uint64_t t64 = time_us_64();
    printf("%lu\r\n", t64);
    sleep_ms(200);

    // Get omplete 64-bit `CTR` value as absolute_time_t.
    // Since you cannot print absolute_time_t, convert it to uint64_t and print it.
    absolute_time_t tAbs = get_absolute_time();
    t64 = to_us_since_boot(tAbs);
    printf("%lu\r\n", t64);
    sleep_ms(300);

    // Create a time value in future.
    // Keep checking whether the value is reached or not
    tAbs = make_timeout_time_us(400000);
    while(!time_reached(tAbs))
    {
        printf("%luus has not elapsed since the code started running.", to_us_since_boot(tAbs));
        sleep_ms(100);
    }
    printf("%luus has passed since the code started running.", time_us_64());
}

int main()
{
    setup();
    while (true)
        loop();
}