mbed official / mbed-dev

mbed library sources. Supersedes mbed-src.

Dependents:   Nucleo_Hello_Encoder BLE_iBeaconScan AM1805_DEMO DISCO-F429ZI_ExportTemplate1 ... more

targets/TARGET_Silicon_Labs/TARGET_EFM32/emlib/src/em_burtc.c@179:b0033dcd6934, 2017-12-07 (annotated)

Committer:
AnnaBridge
Date:
Thu Dec 07 14:01:42 2017 +0000
Revision:
179:b0033dcd6934
Parent:
161:2cc1468da177 
mbed-dev library. Release version 157

Who changed what in which revision?

UserRevisionLine numberNew contents of line
<> 144:ef7eb2e8f9f7 1 /***************************************************************************//**
<> 144:ef7eb2e8f9f7 2 * @file em_burtc.c
<> 144:ef7eb2e8f9f7 3 * @brief Backup Real Time Counter (BURTC) Peripheral API
AnnaBridge 179:b0033dcd6934 4 * @version 5.3.3
<> 144:ef7eb2e8f9f7 5 *******************************************************************************
AnnaBridge 179:b0033dcd6934 6 * # License
<> 150:02e0a0aed4ec 7 * <b>Copyright 2016 Silicon Laboratories, Inc. http://www.silabs.com</b>
<> 144:ef7eb2e8f9f7 8 *******************************************************************************
<> 144:ef7eb2e8f9f7 9 *
<> 144:ef7eb2e8f9f7 10 * Permission is granted to anyone to use this software for any purpose,
<> 144:ef7eb2e8f9f7 11 * including commercial applications, and to alter it and redistribute it
<> 144:ef7eb2e8f9f7 12 * freely, subject to the following restrictions:
<> 144:ef7eb2e8f9f7 13 *
<> 144:ef7eb2e8f9f7 14 * 1. The origin of this software must not be misrepresented; you must not
<> 144:ef7eb2e8f9f7 15 * claim that you wrote the original software.
<> 144:ef7eb2e8f9f7 16 * 2. Altered source versions must be plainly marked as such, and must not be
<> 144:ef7eb2e8f9f7 17 * misrepresented as being the original software.
<> 144:ef7eb2e8f9f7 18 * 3. This notice may not be removed or altered from any source distribution.
<> 144:ef7eb2e8f9f7 19 *
<> 144:ef7eb2e8f9f7 20 * DISCLAIMER OF WARRANTY/LIMITATION OF REMEDIES: Silicon Labs has no
<> 144:ef7eb2e8f9f7 21 * obligation to support this Software. Silicon Labs is providing the
<> 144:ef7eb2e8f9f7 22 * Software "AS IS", with no express or implied warranties of any kind,
<> 144:ef7eb2e8f9f7 23 * including, but not limited to, any implied warranties of merchantability
<> 144:ef7eb2e8f9f7 24 * or fitness for any particular purpose or warranties against infringement
<> 144:ef7eb2e8f9f7 25 * of any proprietary rights of a third party.
<> 144:ef7eb2e8f9f7 26 *
<> 144:ef7eb2e8f9f7 27 * Silicon Labs will not be liable for any consequential, incidental, or
<> 144:ef7eb2e8f9f7 28 * special damages, or any other relief, or for any claim by any third party,
<> 144:ef7eb2e8f9f7 29 * arising from your use of this Software.
<> 144:ef7eb2e8f9f7 30 *
<> 144:ef7eb2e8f9f7 31 ******************************************************************************/
<> 144:ef7eb2e8f9f7 32
<> 144:ef7eb2e8f9f7 33 #include "em_burtc.h"
<> 144:ef7eb2e8f9f7 34 #if defined(BURTC_PRESENT)
<> 144:ef7eb2e8f9f7 35
<> 144:ef7eb2e8f9f7 36 /***************************************************************************//**
<> 150:02e0a0aed4ec 37 * @addtogroup emlib
<> 144:ef7eb2e8f9f7 38 * @{
<> 144:ef7eb2e8f9f7 39 ******************************************************************************/
<> 144:ef7eb2e8f9f7 40
<> 144:ef7eb2e8f9f7 41 /***************************************************************************//**
<> 144:ef7eb2e8f9f7 42 * @addtogroup BURTC
<> 144:ef7eb2e8f9f7 43 * @brief Backup Real Time Counter (BURTC) Peripheral API
<> 150:02e0a0aed4ec 44 * @details
<> 150:02e0a0aed4ec 45 * This module contains functions to control the BURTC peripheral of Silicon
<> 150:02e0a0aed4ec 46 * Labs 32-bit MCUs. The Backup Real Time Counter allows timekeeping in all
<> 150:02e0a0aed4ec 47 * energy modes. The Backup RTC is also available when the system is in backup
<> 150:02e0a0aed4ec 48 * mode.
<> 144:ef7eb2e8f9f7 49 * @{
<> 144:ef7eb2e8f9f7 50 ******************************************************************************/
<> 144:ef7eb2e8f9f7 51
<> 144:ef7eb2e8f9f7 52 /*******************************************************************************
<> 144:ef7eb2e8f9f7 53 ******************************* DEFINES ***********************************
<> 144:ef7eb2e8f9f7 54 ******************************************************************************/
<> 144:ef7eb2e8f9f7 55
<> 144:ef7eb2e8f9f7 56 /*******************************************************************************
<> 144:ef7eb2e8f9f7 57 ************************** LOCAL FUNCTIONS ********************************
<> 144:ef7eb2e8f9f7 58 ******************************************************************************/
<> 144:ef7eb2e8f9f7 59
<> 144:ef7eb2e8f9f7 60 /** @cond DO_NOT_INCLUDE_WITH_DOXYGEN */
<> 144:ef7eb2e8f9f7 61 /***************************************************************************//**
<> 144:ef7eb2e8f9f7 62 * @brief Convert dividend to prescaler logarithmic value. Only works for even
<> 144:ef7eb2e8f9f7 63 * numbers equal to 2^n
<> 144:ef7eb2e8f9f7 64 * @param[in] div Unscaled dividend,
<> 144:ef7eb2e8f9f7 65 * @return Base 2 logarithm of input, as used by fixed prescalers
<> 144:ef7eb2e8f9f7 66 ******************************************************************************/
<> 144:ef7eb2e8f9f7 67 __STATIC_INLINE uint32_t divToLog2(uint32_t div)
<> 144:ef7eb2e8f9f7 68 {
<> 144:ef7eb2e8f9f7 69 uint32_t log2;
<> 144:ef7eb2e8f9f7 70
<> 144:ef7eb2e8f9f7 71 /* Prescaler accepts an argument of 128 or less, valid values being 2^n */
<> 144:ef7eb2e8f9f7 72 EFM_ASSERT((div > 0) && (div <= 32768));
<> 144:ef7eb2e8f9f7 73
<> 144:ef7eb2e8f9f7 74 /* Count leading zeroes and "reverse" result, Cortex-M3 intrinsic */
<> 144:ef7eb2e8f9f7 75 log2 = (31 - __CLZ(div));
<> 144:ef7eb2e8f9f7 76
<> 144:ef7eb2e8f9f7 77 return log2;
<> 144:ef7eb2e8f9f7 78 }
<> 144:ef7eb2e8f9f7 79
<> 144:ef7eb2e8f9f7 80 /***************************************************************************//**
<> 144:ef7eb2e8f9f7 81 * @brief
<> 144:ef7eb2e8f9f7 82 * Wait for ongoing sync of register(s) to low frequency domain to complete.
<> 144:ef7eb2e8f9f7 83 *
<> 144:ef7eb2e8f9f7 84 * @param[in] mask
<> 144:ef7eb2e8f9f7 85 * Bitmask corresponding to SYNCBUSY register defined bits, indicating
<> 144:ef7eb2e8f9f7 86 * registers that must complete any ongoing synchronization.
<> 144:ef7eb2e8f9f7 87 ******************************************************************************/
<> 144:ef7eb2e8f9f7 88 __STATIC_INLINE void regSync(uint32_t mask)
<> 144:ef7eb2e8f9f7 89 {
<> 144:ef7eb2e8f9f7 90 /* Avoid deadlock if modifying the same register twice when freeze mode is
<> 144:ef7eb2e8f9f7 91 activated, or when no clock is selected for the BURTC. If no clock is
<> 144:ef7eb2e8f9f7 92 selected, then the sync is done once the clock source is set. */
<> 144:ef7eb2e8f9f7 93 if ((BURTC->FREEZE & BURTC_FREEZE_REGFREEZE)
AnnaBridge 179:b0033dcd6934 94 || ((BURTC->CTRL & _BURTC_CTRL_CLKSEL_MASK) == BURTC_CTRL_CLKSEL_NONE)) {
<> 144:ef7eb2e8f9f7 95 return;
<> 144:ef7eb2e8f9f7 96 }
<> 144:ef7eb2e8f9f7 97 /* Wait for any pending previous write operation to have been completed */
<> 144:ef7eb2e8f9f7 98 /* in low frequency domain. This is only required for the Gecko Family */
<> 144:ef7eb2e8f9f7 99 while (BURTC->SYNCBUSY & mask)
<> 144:ef7eb2e8f9f7 100 ;
<> 144:ef7eb2e8f9f7 101 }
<> 144:ef7eb2e8f9f7 102 /** @endcond */
<> 144:ef7eb2e8f9f7 103
<> 144:ef7eb2e8f9f7 104 /*******************************************************************************
<> 144:ef7eb2e8f9f7 105 ************************** GLOBAL FUNCTIONS *******************************
<> 144:ef7eb2e8f9f7 106 ******************************************************************************/
<> 144:ef7eb2e8f9f7 107
<> 144:ef7eb2e8f9f7 108 /***************************************************************************//**
<> 144:ef7eb2e8f9f7 109 * @brief Initialize BURTC
<> 144:ef7eb2e8f9f7 110 *
<> 144:ef7eb2e8f9f7 111 * @details
<> 144:ef7eb2e8f9f7 112 * Configures the BURTC peripheral.
<> 144:ef7eb2e8f9f7 113 *
<> 144:ef7eb2e8f9f7 114 * @note
<> 144:ef7eb2e8f9f7 115 * Before initialization, BURTC module must first be enabled by clearing the
<> 144:ef7eb2e8f9f7 116 * reset bit in the RMU, i.e.
<> 144:ef7eb2e8f9f7 117 * @verbatim
<> 144:ef7eb2e8f9f7 118 * RMU_ResetControl(rmuResetBU, rmuResetModeClear);
<> 144:ef7eb2e8f9f7 119 * @endverbatim
<> 144:ef7eb2e8f9f7 120 * Compare channel 0 must be configured outside this function, before
<> 144:ef7eb2e8f9f7 121 * initialization if enable is set to true. The counter will always be reset.
<> 144:ef7eb2e8f9f7 122 *
<> 144:ef7eb2e8f9f7 123 * @param[in] burtcInit
<> 144:ef7eb2e8f9f7 124 * Pointer to BURTC initialization structure
<> 144:ef7eb2e8f9f7 125 ******************************************************************************/
<> 144:ef7eb2e8f9f7 126 void BURTC_Init(const BURTC_Init_TypeDef *burtcInit)
<> 144:ef7eb2e8f9f7 127 {
<> 144:ef7eb2e8f9f7 128 uint32_t ctrl;
<> 144:ef7eb2e8f9f7 129 uint32_t presc;
<> 144:ef7eb2e8f9f7 130
<> 144:ef7eb2e8f9f7 131 /* Check initializer structure integrity */
<> 144:ef7eb2e8f9f7 132 EFM_ASSERT(burtcInit != (BURTC_Init_TypeDef *) 0);
<> 144:ef7eb2e8f9f7 133 /* Clock divider must be between 1 and 128, really on the form 2^n */
<> 144:ef7eb2e8f9f7 134 EFM_ASSERT((burtcInit->clkDiv >= 1) && (burtcInit->clkDiv <= 128));
<> 144:ef7eb2e8f9f7 135 /* Ignored compare bits during low power operation must be less than 7 */
<> 144:ef7eb2e8f9f7 136 /* Note! Giant Gecko revision C errata, do NOT use LPCOMP=7 */
<> 144:ef7eb2e8f9f7 137 EFM_ASSERT(burtcInit->lowPowerComp <= 6);
<> 144:ef7eb2e8f9f7 138 /* You cannot enable the BURTC if mode is set to disabled */
AnnaBridge 179:b0033dcd6934 139 EFM_ASSERT((burtcInit->enable == false)
AnnaBridge 179:b0033dcd6934 140 || ((burtcInit->enable == true)
AnnaBridge 179:b0033dcd6934 141 && (burtcInit->mode != burtcModeDisable)));
<> 144:ef7eb2e8f9f7 142 /* Low power mode is only available with LFRCO or LFXO as clock source */
<> 144:ef7eb2e8f9f7 143 EFM_ASSERT((burtcInit->clkSel != burtcClkSelULFRCO)
<> 144:ef7eb2e8f9f7 144 || ((burtcInit->clkSel == burtcClkSelULFRCO)
AnnaBridge 179:b0033dcd6934 145 && (burtcInit->lowPowerMode == burtcLPDisable)));
<> 144:ef7eb2e8f9f7 146
<> 144:ef7eb2e8f9f7 147 /* Calculate prescaler value from clock divider input */
<> 144:ef7eb2e8f9f7 148 /* Note! If clock select (clkSel) is ULFRCO, a clock divisor (clkDiv) of
<> 144:ef7eb2e8f9f7 149 value 1 will select a 2kHz ULFRCO clock, while any other value will
<> 144:ef7eb2e8f9f7 150 select a 1kHz ULFRCO clock source. */
<> 144:ef7eb2e8f9f7 151 presc = divToLog2(burtcInit->clkDiv);
<> 144:ef7eb2e8f9f7 152
<> 144:ef7eb2e8f9f7 153 /* Make sure all registers are updated simultaneously */
AnnaBridge 179:b0033dcd6934 154 if (burtcInit->enable) {
<> 144:ef7eb2e8f9f7 155 BURTC_FreezeEnable(true);
<> 144:ef7eb2e8f9f7 156 }
<> 144:ef7eb2e8f9f7 157
<> 144:ef7eb2e8f9f7 158 /* Modification of LPMODE register requires sync with potential ongoing
<> 144:ef7eb2e8f9f7 159 * register updates in LF domain. */
<> 144:ef7eb2e8f9f7 160 regSync(BURTC_SYNCBUSY_LPMODE);
<> 144:ef7eb2e8f9f7 161
<> 144:ef7eb2e8f9f7 162 /* Configure low power mode */
<> 144:ef7eb2e8f9f7 163 BURTC->LPMODE = (uint32_t) (burtcInit->lowPowerMode);
<> 144:ef7eb2e8f9f7 164
<> 144:ef7eb2e8f9f7 165 /* New configuration */
<> 144:ef7eb2e8f9f7 166 ctrl = (BURTC_CTRL_RSTEN
<> 144:ef7eb2e8f9f7 167 | (burtcInit->mode)
<> 144:ef7eb2e8f9f7 168 | (burtcInit->debugRun << _BURTC_CTRL_DEBUGRUN_SHIFT)
<> 144:ef7eb2e8f9f7 169 | (burtcInit->compare0Top << _BURTC_CTRL_COMP0TOP_SHIFT)
<> 144:ef7eb2e8f9f7 170 | (burtcInit->lowPowerComp << _BURTC_CTRL_LPCOMP_SHIFT)
<> 144:ef7eb2e8f9f7 171 | (presc << _BURTC_CTRL_PRESC_SHIFT)
<> 144:ef7eb2e8f9f7 172 | (burtcInit->clkSel)
<> 144:ef7eb2e8f9f7 173 | (burtcInit->timeStamp << _BURTC_CTRL_BUMODETSEN_SHIFT));
<> 144:ef7eb2e8f9f7 174
<> 144:ef7eb2e8f9f7 175 /* Clear interrupts */
<> 144:ef7eb2e8f9f7 176 BURTC_IntClear(0xFFFFFFFF);
<> 144:ef7eb2e8f9f7 177
<> 144:ef7eb2e8f9f7 178 /* Set new configuration */
<> 144:ef7eb2e8f9f7 179 BURTC->CTRL = ctrl;
<> 144:ef7eb2e8f9f7 180
<> 144:ef7eb2e8f9f7 181 /* Enable BURTC and counter */
AnnaBridge 179:b0033dcd6934 182 if (burtcInit->enable) {
<> 144:ef7eb2e8f9f7 183 /* To enable BURTC counter, we need to disable reset */
<> 144:ef7eb2e8f9f7 184 BURTC_Enable(true);
<> 144:ef7eb2e8f9f7 185
<> 144:ef7eb2e8f9f7 186 /* Clear freeze */
<> 144:ef7eb2e8f9f7 187 BURTC_FreezeEnable(false);
<> 144:ef7eb2e8f9f7 188 }
<> 144:ef7eb2e8f9f7 189 }
<> 144:ef7eb2e8f9f7 190
<> 144:ef7eb2e8f9f7 191 /***************************************************************************//**
<> 144:ef7eb2e8f9f7 192 * @brief Set BURTC compare channel
<> 144:ef7eb2e8f9f7 193 *
<> 144:ef7eb2e8f9f7 194 * @param[in] comp Compare channel index, must be 0 for Giant / Leopard Gecko
<> 144:ef7eb2e8f9f7 195 *
<> 144:ef7eb2e8f9f7 196 * @param[in] value New compare value
<> 144:ef7eb2e8f9f7 197 ******************************************************************************/
<> 144:ef7eb2e8f9f7 198 void BURTC_CompareSet(unsigned int comp, uint32_t value)
<> 144:ef7eb2e8f9f7 199 {
<> 144:ef7eb2e8f9f7 200 (void) comp; /* Unused parameter when EFM_ASSERT is undefined. */
<> 144:ef7eb2e8f9f7 201
<> 144:ef7eb2e8f9f7 202 EFM_ASSERT(comp == 0);
<> 144:ef7eb2e8f9f7 203
<> 144:ef7eb2e8f9f7 204 /* Modification of COMP0 register requires sync with potential ongoing
<> 144:ef7eb2e8f9f7 205 * register updates in LF domain. */
<> 144:ef7eb2e8f9f7 206 regSync(BURTC_SYNCBUSY_COMP0);
<> 144:ef7eb2e8f9f7 207
<> 144:ef7eb2e8f9f7 208 /* Configure compare channel 0 */
<> 144:ef7eb2e8f9f7 209 BURTC->COMP0 = value;
<> 144:ef7eb2e8f9f7 210 }
<> 144:ef7eb2e8f9f7 211
<> 144:ef7eb2e8f9f7 212 /***************************************************************************//**
<> 144:ef7eb2e8f9f7 213 * @brief Get BURTC compare value
<> 144:ef7eb2e8f9f7 214 *
<> 144:ef7eb2e8f9f7 215 * @param[in] comp Compare channel index value, must be 0 for Giant/Leopard.
<> 144:ef7eb2e8f9f7 216 *
<> 144:ef7eb2e8f9f7 217 * @return Currently configured value for this compare channel
<> 144:ef7eb2e8f9f7 218 ******************************************************************************/
<> 144:ef7eb2e8f9f7 219 uint32_t BURTC_CompareGet(unsigned int comp)
<> 144:ef7eb2e8f9f7 220 {
<> 144:ef7eb2e8f9f7 221 (void) comp; /* Unused parameter when EFM_ASSERT is undefined. */
<> 144:ef7eb2e8f9f7 222
<> 144:ef7eb2e8f9f7 223 EFM_ASSERT(comp == 0);
<> 144:ef7eb2e8f9f7 224
<> 144:ef7eb2e8f9f7 225 return BURTC->COMP0;
<> 144:ef7eb2e8f9f7 226 }
<> 144:ef7eb2e8f9f7 227
<> 144:ef7eb2e8f9f7 228 /***************************************************************************//**
<> 144:ef7eb2e8f9f7 229 * @brief Reset counter
<> 144:ef7eb2e8f9f7 230 ******************************************************************************/
<> 144:ef7eb2e8f9f7 231 void BURTC_CounterReset(void)
<> 144:ef7eb2e8f9f7 232 {
<> 144:ef7eb2e8f9f7 233 /* Set and clear reset bit */
<> 144:ef7eb2e8f9f7 234 BUS_RegBitWrite(&BURTC->CTRL, _BURTC_CTRL_RSTEN_SHIFT, 1);
<> 144:ef7eb2e8f9f7 235 BUS_RegBitWrite(&BURTC->CTRL, _BURTC_CTRL_RSTEN_SHIFT, 0);
<> 144:ef7eb2e8f9f7 236 }
<> 144:ef7eb2e8f9f7 237
<> 144:ef7eb2e8f9f7 238 /***************************************************************************//**
<> 144:ef7eb2e8f9f7 239 * @brief
<> 144:ef7eb2e8f9f7 240 * Restore BURTC to reset state
<> 144:ef7eb2e8f9f7 241 * @note
<> 144:ef7eb2e8f9f7 242 * Before accessing the BURTC, BURSTEN in RMU->CTRL must be cleared.
<> 144:ef7eb2e8f9f7 243 * LOCK will not be reset to default value, as this will disable access
<> 144:ef7eb2e8f9f7 244 * to core BURTC registers.
<> 144:ef7eb2e8f9f7 245 ******************************************************************************/
<> 144:ef7eb2e8f9f7 246 void BURTC_Reset(void)
<> 144:ef7eb2e8f9f7 247 {
<> 144:ef7eb2e8f9f7 248 bool buResetState;
<> 144:ef7eb2e8f9f7 249
<> 144:ef7eb2e8f9f7 250 /* Read reset state, set reset and restore state */
<> 144:ef7eb2e8f9f7 251 buResetState = BUS_RegBitRead(&RMU->CTRL, _RMU_CTRL_BURSTEN_SHIFT);
<> 144:ef7eb2e8f9f7 252 BUS_RegBitWrite(&RMU->CTRL, _RMU_CTRL_BURSTEN_SHIFT, 1);
<> 144:ef7eb2e8f9f7 253 BUS_RegBitWrite(&RMU->CTRL, _RMU_CTRL_BURSTEN_SHIFT, buResetState);
<> 144:ef7eb2e8f9f7 254 }
<> 144:ef7eb2e8f9f7 255
<> 144:ef7eb2e8f9f7 256 /***************************************************************************//**
<> 144:ef7eb2e8f9f7 257 * @brief
<> 144:ef7eb2e8f9f7 258 * Get clock frequency of the BURTC.
<> 144:ef7eb2e8f9f7 259 *
<> 144:ef7eb2e8f9f7 260 * @return
<> 144:ef7eb2e8f9f7 261 * The current frequency in Hz.
<> 144:ef7eb2e8f9f7 262 ******************************************************************************/
<> 144:ef7eb2e8f9f7 263 uint32_t BURTC_ClockFreqGet(void)
<> 144:ef7eb2e8f9f7 264 {
<> 144:ef7eb2e8f9f7 265 uint32_t clkSel;
<> 144:ef7eb2e8f9f7 266 uint32_t clkDiv;
<> 144:ef7eb2e8f9f7 267 uint32_t frequency;
<> 144:ef7eb2e8f9f7 268
<> 144:ef7eb2e8f9f7 269 clkSel = BURTC->CTRL & _BURTC_CTRL_CLKSEL_MASK;
<> 144:ef7eb2e8f9f7 270 clkDiv = (BURTC->CTRL & _BURTC_CTRL_PRESC_MASK) >> _BURTC_CTRL_PRESC_SHIFT;
<> 144:ef7eb2e8f9f7 271
AnnaBridge 179:b0033dcd6934 272 switch (clkSel) {
<> 144:ef7eb2e8f9f7 273 /** Ultra low frequency (1 kHz) clock */
<> 144:ef7eb2e8f9f7 274 case BURTC_CTRL_CLKSEL_ULFRCO:
AnnaBridge 179:b0033dcd6934 275 if (_BURTC_CTRL_PRESC_DIV1 == clkDiv) {
<> 144:ef7eb2e8f9f7 276 frequency = 2000; /* 2KHz when clock divisor is 1. */
AnnaBridge 179:b0033dcd6934 277 } else {
<> 144:ef7eb2e8f9f7 278 frequency = SystemULFRCOClockGet(); /* 1KHz when divisor is different
<> 144:ef7eb2e8f9f7 279 from 1. */
<> 144:ef7eb2e8f9f7 280 }
<> 144:ef7eb2e8f9f7 281 break;
<> 144:ef7eb2e8f9f7 282
<> 144:ef7eb2e8f9f7 283 /** Low frequency RC oscillator */
<> 144:ef7eb2e8f9f7 284 case BURTC_CTRL_CLKSEL_LFRCO:
<> 144:ef7eb2e8f9f7 285 frequency = SystemLFRCOClockGet() / (1 << clkDiv); /* freq=32768/2^clkDiv */
<> 144:ef7eb2e8f9f7 286 break;
<> 144:ef7eb2e8f9f7 287
<> 144:ef7eb2e8f9f7 288 /** Low frequency crystal osciallator */
<> 144:ef7eb2e8f9f7 289 case BURTC_CTRL_CLKSEL_LFXO:
<> 144:ef7eb2e8f9f7 290 frequency = SystemLFXOClockGet() / (1 << clkDiv); /* freq=32768/2^clkDiv */
<> 144:ef7eb2e8f9f7 291 break;
<> 144:ef7eb2e8f9f7 292
<> 144:ef7eb2e8f9f7 293 default:
<> 144:ef7eb2e8f9f7 294 /* No clock selected for BURTC. */
<> 144:ef7eb2e8f9f7 295 frequency = 0;
<> 144:ef7eb2e8f9f7 296 }
<> 144:ef7eb2e8f9f7 297 return frequency;
<> 144:ef7eb2e8f9f7 298 }
<> 144:ef7eb2e8f9f7 299
<> 144:ef7eb2e8f9f7 300 /** @} (end addtogroup BURTC) */
<> 150:02e0a0aed4ec 301 /** @} (end addtogroup emlib) */
<> 144:ef7eb2e8f9f7 302
<> 144:ef7eb2e8f9f7 303 #endif /* BURTC_PRESENT */