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
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
|
/*
* Copyright 2012 Benjamin Vernoux
*
* This file is part of HackRF.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
#include <libopencm3/lpc43xx/m4/nvic.h>
#include <libopencm3/cm3/systick.h>
#include <libopencm3/cm3/scs.h>
#include "hackrf_core.h"
/* Global counter incremented by SysTick Interrupt each millisecond */
volatile uint32_t g_ulSysTickCount;
uint32_t g_NbCyclePerSecond;
void systick_setup(void)
{
uint32_t systick_reload_val;
g_ulSysTickCount = 0;
/* Disable IRQ globally */
__asm__("cpsid i");
/* Set processor Clock as Source Clock */
systick_set_clocksource(STK_CTRL_CLKSOURCE);
/* Get SysTick calibration value to obtain by default 1 tick = 10ms */
systick_reload_val = systick_get_calib();
/*
* Calibration seems wrong on LPC43xx(TBC) for default Freq it assume System Clock is 12MHz but it is 12*17=204MHz
* Fix the Calibration value bu multiplication by 17
*/
systick_reload_val = (systick_reload_val*17);
/* To obtain 1ms per tick just divide by 10 the 10ms base tick and set the reload */
systick_reload_val = systick_reload_val/10;
systick_set_reload(systick_reload_val);
systick_interrupt_enable();
/* Start counting. */
systick_counter_enable();
/* Set SysTick Priority to maximum */
nvic_set_priority(NVIC_SYSTICK_IRQ, 0xFF);
/* Enable IRQ globally */
__asm__("cpsie i");
}
void scs_dwt_cycle_counter_enabled(void)
{
SCS_DEMCR |= SCS_DEMCR_TRCENA;
SCS_DWT_CTRL |= SCS_DWT_CTRL_CYCCNTENA;
}
uint32_t sys_tick_get_time_ms(void)
{
return g_ulSysTickCount;
}
uint32_t sys_tick_delta_time_ms(uint32_t start, uint32_t end)
{
#define MAX_T_U32 ((2^32)-1)
uint32_t diff;
if(end > start)
{
diff=end-start;
}else
{
diff=MAX_T_U32-(start-end)+1;
}
return diff;
}
void sys_tick_wait_time_ms(uint32_t wait_ms)
{
uint32_t start, end;
uint32_t tickms;
start = sys_tick_get_time_ms();
do
{
end = sys_tick_get_time_ms();
tickms = sys_tick_delta_time_ms(start, end);
}while(tickms < wait_ms);
}
/* Called each 1ms/1000Hz by interrupt
1) Count the number of cycle per second.
2) Increment g_ulSysTickCount counter.
*/
void sys_tick_handler(void)
{
if(g_ulSysTickCount==0)
{
/* Clear Cycle Counter*/
SCS_DWT_CYCCNT = 0;
}else if(g_ulSysTickCount==1000)
{
/* Capture number of cycle elapsed during 1 second */
g_NbCyclePerSecond = SCS_DWT_CYCCNT;
}
g_ulSysTickCount++;
}
int main(void)
{
pin_setup();
enable_1v8_power();
cpu_clock_init();
scs_dwt_cycle_counter_enabled();
systick_setup();
led_on(LED1);
led_on(LED2);
led_on(LED3);
while (1)
{
led_on(LED1);
led_on(LED2);
led_on(LED3);
sys_tick_wait_time_ms(500);
led_off(LED1);
led_off(LED2);
led_off(LED3);
sys_tick_wait_time_ms(500);
}
return 0;
}
|
