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
|
/****************************************************************************
* arch/arm/src/stm32/stm32_lse.c
*
* Copyright (C) 2009, 2011, 2015 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.orgr>
*
* 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.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include "up_arch.h"
#include "stm32_pwr.h"
#include "stm32_rcc.h"
#include "stm32_waste.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: stm32_rcc_enablelse
*
* Description:
* Enable the External Low-Speed (LSE) oscillator.
*
* Todo:
* Check for LSE good timeout and return with -1,
*
****************************************************************************/
void stm32_rcc_enablelse(void)
{
/* The LSE is in the RTC domain and write access is denied to this domain
* after reset, you have to enable write access using DBP bit in the PWR CR
* register before to configuring the LSE.
*/
stm32_pwr_enablebkp(true);
#if defined(CONFIG_STM32_STM32L15XX)
/* Enable the External Low-Speed (LSE) oscillator by setting the LSEON bit
* the RCC CSR register.
*/
modifyreg32(STM32_RCC_CSR, 0, RCC_CSR_LSEON);
/* Wait for the LSE clock to be ready */
while ((getreg32(STM32_RCC_CSR) & RCC_CSR_LSERDY) == 0)
{
up_waste();
}
#else
/* Enable the External Low-Speed (LSE) oscillator by setting the LSEON bit
* the RCC BDCR register.
*/
modifyreg16(STM32_RCC_BDCR, 0, RCC_BDCR_LSEON);
/* Wait for the LSE clock to be ready */
while ((getreg16(STM32_RCC_BDCR) & RCC_BDCR_LSERDY) == 0)
{
up_waste();
}
#endif
stm32_pwr_enablebkp(false);
}
|
