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
|
/* SPDX-License-Identifier: BSD-2-Clause */
/**
* @file
*
* @ingroup RTEMSBSPsARMLPC176X_clocks
*
* @brief System clocks.
*/
/*
* Copyright (c) 2008-2012 embedded brains GmbH. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <bsp.h>
#include <bsp/system-clocks.h>
/**
* @brief Internal RC oscillator frequency in [Hz].
*/
#define LPC176X_OSCILLATOR_INTERNAL 4000000u
#ifndef LPC176X_OSCILLATOR_MAIN
#error "unknown main oscillator frequency"
#endif
#ifndef LPC176X_OSCILLATOR_RTC
#error "unknown RTC oscillator frequency"
#endif
inline unsigned lpc176x_sysclk( void );
void lpc176x_timer_initialize( void )
{
/* Reset timer */
LPC176X_T1TCR = TCR_RST;
/* Set timer mode */
LPC176X_T1CTCR = 0u;
/* Set prescaler to zero */
LPC176X_T1PR = 0u;
/* Reset all interrupt flags */
LPC176X_T1IR = 0xffU;
/* Do not stop on a match */
LPC176X_T1MCR = 0u;
/* No captures */
LPC176X_T1CCR = 0u;
/* Start timer */
LPC176X_T1TCR = TCR_EN;
}
void lpc176x_micro_seconds_delay( const unsigned us )
{
const unsigned start = lpc176x_get_timer1();
const unsigned delay = us * ( LPC176X_PCLK / 1000000u );
unsigned elapsed = 0u;
do {
elapsed = lpc176x_get_timer1() - start;
} while ( elapsed < delay );
}
unsigned lpc176x_sysclk( void )
{
return ( LPC176X_SCB.clksrcsel & LPC176X_SCB_CLKSRCSEL_CLKSRC ) != 0u ?
LPC176X_OSCILLATOR_MAIN : LPC176X_OSCILLATOR_INTERNAL;
}
unsigned lpc176x_pllclk( void )
{
const unsigned sysclk = lpc176x_sysclk();
const unsigned pllstat = ( LPC176X_SCB.pll_0 ).stat;
const unsigned enabled_and_locked = LPC176X_PLL_STAT_PLLE |
LPC176X_PLL_STAT_PLOCK;
unsigned pllclk = 0u;
if ( ( pllstat & enabled_and_locked ) == enabled_and_locked ) {
unsigned m = LPC176X_PLL_SEL_MSEL_GET( pllstat ) + 1u;
pllclk = sysclk * m;
}
/* else implies that the pllstat is unlocked. Also,
there is nothing to do. */
return pllclk;
}
unsigned lpc176x_cclk( void )
{
const unsigned cclksel = LPC176X_SCB.cclksel;
unsigned cclk_in = 0u;
unsigned cclk = 0u;
if ( ( cclksel & LPC176X_SCB_CCLKSEL_CCLKSEL ) != 0u ) {
cclk_in = lpc176x_pllclk();
} else {
cclk_in = lpc176x_sysclk();
}
cclk = cclk_in / LPC176X_SCB_CCLKSEL_CCLKDIV_GET( cclksel );
return cclk;
}
uint32_t _CPU_Counter_frequency(void)
{
return LPC176X_PCLK;
}
CPU_Counter_ticks _CPU_Counter_read( void )
{
return lpc176x_get_timer1();
}
|
