blob: a28824c798e88b48d80bb11e52a50715d52c8f80 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
|
#include "project.h"
static volatile uint32_t ticks;
static uint32_t scale = 7;
unsigned led1 = 1000, led2 = 1000;
void
delay_us (uint32_t d)
{
d *= scale;
while (d--)
__asm__ ("nop");
}
void
sys_tick_handler (void)
{
ticks++;
cdcacm_tick();
if (led1)
led1--;
if (led2)
led2--;
if (led1)
gpio_clear (LED1_BANK, LED1_GPIO);
else
gpio_set (LED1_BANK, LED1_GPIO);
if (led2)
gpio_clear (LED2_BANK, LED2_GPIO);
else
gpio_set (LED2_BANK, LED2_GPIO);
}
void
ticker_init (void)
{
uint32_t v, w;
/*Start periodic timer */
systick_set_clocksource (STK_CSR_CLKSOURCE_AHB_DIV8);
/* 48MHz / 8 = > 6Mhz */
systick_set_reload (6000);
/* 6MHz / 6000 => 1kHz */
systick_interrupt_enable();
systick_counter_enable();
/*Calibrate the delay loop */
do {
scale--;
v = ticks;
while (v == ticks)
;
delay_us (1000);
w = ticks;
v++;
w -= v;
} while (w);
}
|