Sergey Solodunov / mbed-dev

mbed library sources. Supersedes mbed-src.

Fork of mbed-dev by mbed official

targets/hal/TARGET_Atmel/TARGET_SAM_CortexM0P/drivers/services/delay/sam0/systick_counter.c@144:423e1876dc07, 2016-08-02 (annotated)

Committer:
screamer
Date:
Tue Aug 02 14:07:36 2016 +0000
Revision:
144:423e1876dc07
Parent:
15:a81a8d6c1dfe 
Added targets.json file for the supported targets in the release

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mbed_official 15:a81a8d6c1dfe 1 #include "delay.h"
mbed_official 15:a81a8d6c1dfe 2
mbed_official 15:a81a8d6c1dfe 3 /**
mbed_official 15:a81a8d6c1dfe 4 * Value used to calculate ms delay. Default to be used with a 8MHz clock;
mbed_official 15:a81a8d6c1dfe 5 */
mbed_official 15:a81a8d6c1dfe 6 static uint32_t cycles_per_ms = 8000000UL / 1000;
mbed_official 15:a81a8d6c1dfe 7 static uint32_t cycles_per_us = 8000000UL / 1000000;
mbed_official 15:a81a8d6c1dfe 8
mbed_official 15:a81a8d6c1dfe 9 /**
mbed_official 15:a81a8d6c1dfe 10 * \brief Initialize the delay driver.
mbed_official 15:a81a8d6c1dfe 11 *
mbed_official 15:a81a8d6c1dfe 12 * This must be called during start up to initialize the delay routine with
mbed_official 15:a81a8d6c1dfe 13 * the current used main clock. It must run any time the main CPU clock is changed.
mbed_official 15:a81a8d6c1dfe 14 */
mbed_official 15:a81a8d6c1dfe 15 void delay_init(void)
mbed_official 15:a81a8d6c1dfe 16 {
mbed_official 15:a81a8d6c1dfe 17 cycles_per_ms = system_gclk_gen_get_hz(0);
mbed_official 15:a81a8d6c1dfe 18 cycles_per_ms /= 1000;
mbed_official 15:a81a8d6c1dfe 19 cycles_per_us = cycles_per_ms / 1000;
mbed_official 15:a81a8d6c1dfe 20
mbed_official 15:a81a8d6c1dfe 21 SysTick->CTRL = SysTick_CTRL_CLKSOURCE_Msk | SysTick_CTRL_ENABLE_Msk;
mbed_official 15:a81a8d6c1dfe 22 }
mbed_official 15:a81a8d6c1dfe 23
mbed_official 15:a81a8d6c1dfe 24 /**
mbed_official 15:a81a8d6c1dfe 25 * \brief Delay loop to delay at least n number of microseconds
mbed_official 15:a81a8d6c1dfe 26 *
mbed_official 15:a81a8d6c1dfe 27 * \param n Number of microseconds to wait
mbed_official 15:a81a8d6c1dfe 28 */
mbed_official 15:a81a8d6c1dfe 29 void delay_cycles_us(
mbed_official 15:a81a8d6c1dfe 30 uint32_t n)
mbed_official 15:a81a8d6c1dfe 31 {
mbed_official 15:a81a8d6c1dfe 32 while (n--) {
mbed_official 15:a81a8d6c1dfe 33 /* Devide up to blocks of 10u */
mbed_official 15:a81a8d6c1dfe 34 delay_cycles(cycles_per_us);
mbed_official 15:a81a8d6c1dfe 35 }
mbed_official 15:a81a8d6c1dfe 36 }
mbed_official 15:a81a8d6c1dfe 37
mbed_official 15:a81a8d6c1dfe 38 /**
mbed_official 15:a81a8d6c1dfe 39 * \brief Delay loop to delay at least n number of milliseconds
mbed_official 15:a81a8d6c1dfe 40 *
mbed_official 15:a81a8d6c1dfe 41 * \param n Number of milliseconds to wait
mbed_official 15:a81a8d6c1dfe 42 */
mbed_official 15:a81a8d6c1dfe 43 void delay_cycles_ms(
mbed_official 15:a81a8d6c1dfe 44 uint32_t n)
mbed_official 15:a81a8d6c1dfe 45 {
mbed_official 15:a81a8d6c1dfe 46 while (n--) {
mbed_official 15:a81a8d6c1dfe 47 /* Devide up to blocks of 1ms */
mbed_official 15:a81a8d6c1dfe 48 delay_cycles(cycles_per_ms);
mbed_official 15:a81a8d6c1dfe 49 }
mbed_official 15:a81a8d6c1dfe 50 }