Portable millisecond timer. More...
#include <inttypes.h>#include <stdbool.h>#include <stddef.h>#include <stdint.h>#include <stdio.h>#include <libopencm3/cm3/systick.h>
Go to the source code of this file.
Classes | |
| struct | __millisec_timer |
| portable millisecond timer More... | |
Macros | |
| #define | MILLISEC_TIMER_SYSTICK_IT void sys_tick_handler(void) { MILLISEC_TIMER_NOW++; } |
| Millisecond timer SysTick interrupt. | |
| #define | MILLISEC_TIMER_AVR_TIMER0_ISR ISR(TIMER0_COMPA_vect) { MILLISEC_TIMER_NOW++; } |
| Millisecond timer SysTick interrupt. | |
| #define | millisec_timer_avr_timer0_setup_16MHz() |
| Setup the systick timer. | |
Typedefs | |
| typedef uint32_t | millisec_timer_unit_t |
| typedef struct __millisec_timer | millisec_timer |
| portable millisecond timer | |
Functions | |
| void | millisec_timer_set_rel (millisec_timer *timer, const millisec_timer_unit_t now, const millisec_timer_unit_t rel) |
| Set timer to expire in the future. | |
| bool | millisec_timer_is_expired (millisec_timer *timer, const millisec_timer_unit_t now) |
| Check if timer has expired & if so, disable it. | |
| bool | millisec_timer_is_expired_repeat (millisec_timer *timer, const millisec_timer_unit_t now) |
| Check if timer has expired & if so, re-enable for the same interval. | |
| void | millisec_timer_systick_setup (uint32_t ahb_frequency) |
| Setup the systick timer. | |
Variables | |
| static uint32_t | MILLISEC_TIMER_NOW = 0 |
| A counter that increments every millisecond. | |
Detailed Description
Portable millisecond timer.
On microcontrollers, MILLISEC_TIMER_NOW will be declared and can be setup to increment every millisecond.
For Cortex-M, put:
1) #include <libopencm3/cm3/nvic.h> at the top of your main file
2) MILLISEC_TIMER_SYSTICK_IT; outside of any function to define the systick interrupt
3) millisec_timer_systick_setup(); with rcc_ahb_frequency as its argument,in the setup portion of your main function. It's probably best to put before other things.
For AVR, put:
1) #include <avr/interrupt.h> #include <avr/io.h> #include <util/atomic.h> at the top of your main file
2) MILLISEC_TIMER_AVR_TIMER0_ISR; outside of any function to define Timer0 ISR.
3) millisec_timer_avr_timer0_setup_16MHz(); in the setup portion of your main function to setup the timer for 16 MHz clock speed.
Definition in file millisec_timer.h.
Macro Definition Documentation
◆ MILLISEC_TIMER_AVR_TIMER0_ISR
| #define MILLISEC_TIMER_AVR_TIMER0_ISR ISR(TIMER0_COMPA_vect) { MILLISEC_TIMER_NOW++; } |
Millisecond timer SysTick interrupt.
Implements an interrupt handler that increments MILLISEC_TIMER_NOW
Definition at line 128 of file millisec_timer.h.
◆ millisec_timer_avr_timer0_setup_16MHz
| #define millisec_timer_avr_timer0_setup_16MHz | ( | ) |
Setup the systick timer.
Configures Timer0 to raise the TIMER0_COMPA interrupt every millisecond.
It's a good idea to use ATOMIC blocks around MILLISEC_TIMER_NOW access.
Definition at line 138 of file millisec_timer.h.
◆ MILLISEC_TIMER_SYSTICK_IT
| #define MILLISEC_TIMER_SYSTICK_IT void sys_tick_handler(void) { MILLISEC_TIMER_NOW++; } |
Millisecond timer SysTick interrupt.
Implements an interrupt handler that increments MILLISEC_TIMER_NOW
Definition at line 111 of file millisec_timer.h.
Typedef Documentation
◆ millisec_timer
| typedef struct __millisec_timer millisec_timer |
portable millisecond timer
It's designed to be easy to use and handle wraparound properly (which happens every 49.7 days for uint32_t).
◆ millisec_timer_unit_t
| typedef uint32_t millisec_timer_unit_t |
Definition at line 47 of file millisec_timer.h.
Function Documentation
◆ millisec_timer_is_expired()
| bool millisec_timer_is_expired | ( | millisec_timer * | timer, |
| const millisec_timer_unit_t | now ) |
Check if timer has expired & if so, disable it.
If timer is enabled and it's expired, return true and disable the timer. If not enabled or the time hasn't expired, return false.
Definition at line 16 of file millisec_timer.c.
◆ millisec_timer_is_expired_repeat()
| bool millisec_timer_is_expired_repeat | ( | millisec_timer * | timer, |
| const millisec_timer_unit_t | now ) |
Check if timer has expired & if so, re-enable for the same interval.
If timer is enabled and it's set time has expired: 1) set the new expiration time to be the old expire time + (old expire time
- old set time) 2) set the new set time to be the old expire time 3) return true. If not enabled or the time hasn't expired, return false.
Definition at line 30 of file millisec_timer.c.
◆ millisec_timer_set_rel()
| void millisec_timer_set_rel | ( | millisec_timer * | timer, |
| const millisec_timer_unit_t | now, | ||
| const millisec_timer_unit_t | rel ) |
Set timer to expire in the future.
Sets and enables timer to expire rel ms in the future.
This sets the set_time to now and the expire_time to set_time + rel
Definition at line 8 of file millisec_timer.c.
◆ millisec_timer_systick_setup()
| void millisec_timer_systick_setup | ( | uint32_t | ahb_frequency | ) |
Setup the systick timer.
Configures the systick timer to raise the interrupt every millisecond.
Definition at line 50 of file millisec_timer.c.
Variable Documentation
◆ MILLISEC_TIMER_NOW
|
static |
A counter that increments every millisecond.
This value will increment every millisecond, if everything is setup correctly.
Definition at line 101 of file millisec_timer.h.
