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
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
|
/***************************************************************************//**
* @file
* @brief Backup Real Time Counter (BURTC) Peripheral API
* @author Energy Micro AS
* @version 3.0.0
*******************************************************************************
* @section License
* <b>(C) Copyright 2012 Energy Micro AS, http://www.energymicro.com</b>
*******************************************************************************
*
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
*
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*
* DISCLAIMER OF WARRANTY/LIMITATION OF REMEDIES: Energy Micro AS has no
* obligation to support this Software. Energy Micro AS is providing the
* Software "AS IS", with no express or implied warranties of any kind,
* including, but not limited to, any implied warranties of merchantability
* or fitness for any particular purpose or warranties against infringement
* of any proprietary rights of a third party.
*
* Energy Micro AS will not be liable for any consequential, incidental, or
* special damages, or any other relief, or for any claim by any third party,
* arising from your use of this Software.
*
******************************************************************************/
#include "em_part.h"
#if defined(BURTC_PRESENT)
#include "em_burtc.h"
#include "em_assert.h"
#include "em_bitband.h"
/***************************************************************************//**
* @addtogroup EM_Library
* @{
******************************************************************************/
/***************************************************************************//**
* @addtogroup BURTC
* @brief Backup Real Time Counter (BURTC) Peripheral API
* @{
******************************************************************************/
/*******************************************************************************
******************************* DEFINES ***********************************
******************************************************************************/
/*******************************************************************************
************************** LOCAL FUNCTIONS ********************************
******************************************************************************/
/***************************************************************************//**
* @brief Convert dividend to prescaler logarithmic value. Only works for even
* numbers equal to 2^n
* @param[in] div Unscaled dividend,
* @return Base 2 logarithm of input, as used by fixed prescalers
******************************************************************************/
__STATIC_INLINE uint32_t BURTC_DivToLog2(uint32_t div)
{
uint32_t log2;
/* Prescaler accepts an argument of 128 or less, valid values being 2^n */
EFM_ASSERT((div > 0) && (div <= 32768));
/* Count leading zeroes and "reverse" result, Cortex-M3 intrinsic */
log2 = (31 - __CLZ(div));
return log2;
}
/*******************************************************************************
************************** GLOBAL FUNCTIONS *******************************
******************************************************************************/
/***************************************************************************//**
* @brief Initialize BURTC
*
* @details
* Configures the BURTC peripheral.
*
* @note
* Before initialization, BURTC module must first be enabled by clearing the
* reset bit in the RMU, i.e.
* @verbatim
* RMU_ResetControl(rmuResetBU, false);
* @endverbatim
* Compare channel 0 must be configured outside this function, before
* initialization if enable is set to true. The counter will always be reset.
*
* @param[in] burtcInit
* Pointer to BURTC initialization structure
******************************************************************************/
void BURTC_Init(const BURTC_Init_TypeDef *burtcInit)
{
uint32_t ctrl;
uint32_t presc;
/* Check initializer structure integrity */
EFM_ASSERT(burtcInit != (BURTC_Init_TypeDef *) 0);
/* Clock divider must be between 1 and 128, really on the form 2^n */
EFM_ASSERT((burtcInit->clkDiv >= 1) && (burtcInit->clkDiv <= 128));
/* Ignored compare bits during low power operation must be less than 7 */
/* Note! Giant Gecko revision C errata, do NOT use LPCOMP=7 */
EFM_ASSERT(burtcInit->lowPowerComp <= 6);
/* You cannot enable the BURTC if mode is set to disabled */
EFM_ASSERT((burtcInit->enable == false) ||
((burtcInit->enable == true) && (burtcInit->mode != burtcModeDisable)));
/* Low power mode is only available with LFRCO or LFXO as clock source */
EFM_ASSERT((burtcInit->clkSel != burtcClkSelULFRCO) ||
((burtcInit->clkSel == burtcClkSelULFRCO) && (burtcInit->lowPowerMode == burtcLPDisable)));
/* Calculate prescaler value from clock divider input */
/* Note! If clock select (clkSel) is ULFRCO, a non-zero clkDiv will select */
/* 1kHz clock source, while any other value will use a 2kHz ULFRCO clock */
presc = BURTC_DivToLog2(burtcInit->clkDiv);
/* Make sure all registers are updated simultaneously */
if (burtcInit->enable)
{
BURTC_FreezeEnable(true);
}
/* Configure low power mode */
BURTC->LPMODE = (uint32_t)(burtcInit->lowPowerMode);
/* New configuration */
ctrl = ((BURTC_CTRL_RSTEN) |
(burtcInit->mode) |
(burtcInit->debugRun << _BURTC_CTRL_DEBUGRUN_SHIFT) |
(burtcInit->compare0Top << _BURTC_CTRL_COMP0TOP_SHIFT) |
(burtcInit->lowPowerComp << _BURTC_CTRL_LPCOMP_SHIFT) |
(presc << _BURTC_CTRL_PRESC_SHIFT) |
(burtcInit->clkSel) |
(burtcInit->timeStamp << _BURTC_CTRL_BUMODETSEN_SHIFT));
/* Clear interrupts */
BURTC->IFC = 0xFFFFFFFF;
/* Set new configuration */
BURTC->CTRL = ctrl;
/* Enable BURTC and counter */
if (burtcInit->enable)
{
/* To enable BURTC counter, we need to disable reset */
BURTC_Enable(true);
/* Clear freeze */
BURTC_FreezeEnable(false);
/* Await synchronization into low frequency domain */
while (BURTC->SYNCBUSY) ;
}
}
/***************************************************************************//**
* @brief Set BURTC compare channel
*
* @param[in] comp Compare channel index, must be 0 for Giant / Leopard Gecko
*
* @param[in] value New compare value
******************************************************************************/
void BURTC_CompareSet(unsigned int comp, uint32_t value)
{
EFM_ASSERT(comp == 0);
/* Configure compare channel 0 */
BURTC->COMP0 = value;
/* Check if freeze or RSTEN is active, if not wait for synchronization of register */
if (BURTC->FREEZE & BURTC_FREEZE_REGFREEZE_FREEZE)
{
return;
}
/* Check if mode is enabled */
if ((BURTC->CTRL & _BURTC_CTRL_MODE_MASK) == BURTC_CTRL_MODE_DISABLE)
{
return;
}
while (BURTC->SYNCBUSY & BURTC_SYNCBUSY_COMP0) ;
}
/***************************************************************************//**
* @brief Get BURTC compare value
*
* @param[in] comp Compare channel index value, must be 0 for Giant/Leopard.
*
* @return Currently configured value for this compare channel
******************************************************************************/
uint32_t BURTC_CompareGet(unsigned int comp)
{
EFM_ASSERT(comp == 0);
return BURTC->COMP0;
}
/***************************************************************************//**
* @brief Reset counter
*
* @param[in] mode New mode of operation, after clearing
******************************************************************************/
void BURTC_CounterReset(void)
{
/* Set and clear reset bit */
BITBAND_Peripheral(&BURTC->CTRL, _BURTC_CTRL_RSTEN_SHIFT, 1);
BITBAND_Peripheral(&BURTC->CTRL, _BURTC_CTRL_RSTEN_SHIFT, 0);
}
/***************************************************************************//**
* @brief
* Restore BURTC to reset state
* @note
* Before accessing the BURTC, BURSTEN in RMU->CTRL must be cleared.
* LOCK will not be reset to default value, as this will disable access
* to core BURTC registers.
******************************************************************************/
void BURTC_Reset(void)
{
/* Verify RMU BURSTEN is disabled */
EFM_ASSERT((RMU->CTRL & RMU_CTRL_BURSTEN) == 0);
/* Restore all essential BURTC registers to default config */
BURTC->CTRL = _BURTC_CTRL_RESETVALUE;
BURTC->IEN = _BURTC_IEN_RESETVALUE;
BURTC->LPMODE = _BURTC_LPMODE_RESETVALUE;
BURTC->LFXOFDET = _BURTC_LFXOFDET_RESETVALUE;
BURTC->POWERDOWN = _BURTC_POWERDOWN_RESETVALUE;
BURTC->FREEZE = _BURTC_FREEZE_RESETVALUE;
}
/** @} (end addtogroup BURTC) */
/** @} (end addtogroup EM_Library) */
#endif /* BURTC_PRESENT */
|
