Paparazzi UAS  v5.0.5_stable-7-g4b8bbb7
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sys_time_arch.h
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23 
32 #ifndef SYS_TIME_ARCH_H
33 #define SYS_TIME_ARCH_H
34 
35 #include "mcu_periph/sys_time.h"
36 
37 #include <libopencm3/stm32/gpio.h>
38 #include <libopencm3/stm32/rcc.h>
39 #include <libopencm3/cm3/systick.h>
40 #include "std.h"
41 
47 static inline uint32_t get_sys_time_usec(void) {
48  return sys_time.nb_sec * 1000000 +
50  usec_of_cpu_ticks(systick_get_reload() - systick_get_value());
51 }
52 
53 /* Generic timer macros */
54 #define SysTimeTimerStart(_t) { _t = get_sys_time_usec(); }
55 #define SysTimeTimer(_t) ( get_sys_time_usec() - (_t))
56 #define SysTimeTimerStop(_t) { _t = ( get_sys_time_usec() - (_t)); }
57 
62 static inline void sys_time_usleep(uint32_t us) {
63  /* duration and end time in SYS_TIME_TICKS */
64  uint32_t d_sys_ticks = sys_time_ticks_of_usec(us);
65  uint32_t end_nb_tick = sys_time.nb_tick + d_sys_ticks;
66 
67  /* remainder in CPU_TICKS */
68  uint32_t rem_cpu_ticks = cpu_ticks_of_usec(us) - d_sys_ticks * sys_time.resolution_cpu_ticks;
69  /* cortex systick counts backwards, end value is reload_value - remainder */
70  uint32_t end_cpu_ticks = systick_get_reload() - rem_cpu_ticks;
71 
72  /* first wait until end time in SYS_TIME_TICKS */
73  while (sys_time.nb_tick < end_nb_tick);
74  /* then wait remaining cpu ticks */
75  while (systick_get_value() > end_cpu_ticks);
76 }
77 
78 #endif /* SYS_TIME_ARCH_H */
static void sys_time_usleep(uint32_t us)
Busy wait in microseconds.
Definition: sys_time_arch.h:62
static uint32_t get_sys_time_usec(void)
Get the time in microseconds since startup.
Definition: sys_time_arch.h:47
static uint32_t usec_of_cpu_ticks(uint32_t cpu_ticks)
Definition: sys_time.h:180
Architecture independent timing functions.
unsigned long uint32_t
Definition: types.h:18
volatile uint32_t nb_sec_rem
remainder of seconds since startup in CPU_TICKS
Definition: sys_time.h:70
volatile uint32_t nb_tick
SYS_TIME_TICKS since startup.
Definition: sys_time.h:71
volatile uint32_t nb_sec
full seconds since startup
Definition: sys_time.h:69
uint32_t resolution_cpu_ticks
sys_time_timer resolution in cpu ticks
Definition: sys_time.h:76
static uint32_t sys_time_ticks_of_usec(uint32_t usec)
Definition: sys_time.h:139
static uint32_t cpu_ticks_of_usec(uint32_t usec)
Definition: sys_time.h:164