1 /***************************************************************************//**
2 * @file
3 * @brief CMSIS Cortex-M3/M4 System Layer for EFR32 devices.
4 *******************************************************************************
5 * # License
6 * <b>Copyright 2020 Silicon Laboratories Inc. www.silabs.com</b>
7 *******************************************************************************
8 *
9 * SPDX-License-Identifier: Zlib
10 *
11 * The licensor of this software is Silicon Laboratories Inc.
12 *
13 * This software is provided 'as-is', without any express or implied
14 * warranty. In no event will the authors be held liable for any damages
15 * arising from the use of this software.
16 *
17 * Permission is granted to anyone to use this software for any purpose,
18 * including commercial applications, and to alter it and redistribute it
19 * freely, subject to the following restrictions:
20 *
21 * 1. The origin of this software must not be misrepresented; you must not
22 * claim that you wrote the original software. If you use this software
23 * in a product, an acknowledgment in the product documentation would be
24 * appreciated but is not required.
25 * 2. Altered source versions must be plainly marked as such, and must not be
26 * misrepresented as being the original software.
27 * 3. This notice may not be removed or altered from any source distribution.
28 *
29 ******************************************************************************/
30
31 #include <stdint.h>
32 #include "em_device.h"
33
34 /*******************************************************************************
35 ****************************** DEFINES ************************************
36 ******************************************************************************/
37
38 /** LFRCO frequency, tuned to below frequency during manufacturing. */
39 #define EFR32_LFRCO_FREQ (32768UL)
40 /** ULFRCO frequency */
41 #define EFR32_ULFRCO_FREQ (1000UL)
42
43 /*******************************************************************************
44 ************************** LOCAL VARIABLES ********************************
45 ******************************************************************************/
46
47 /* System oscillator frequencies. These frequencies are normally constant */
48 /* for a target, but they are made configurable in order to allow run-time */
49 /* handling of different boards. The crystal oscillator clocks can be set */
50 /* compile time to a non-default value by defining respective EFR32_nFXO_FREQ */
51 /* values according to board design. By defining the EFR32_nFXO_FREQ to 0, */
52 /* one indicates that the oscillator is not present, in order to save some */
53 /* SW footprint. */
54
55 #ifndef EFR32_HFRCO_MAX_FREQ
56 /** Maximum HFRCO frequency */
57 #define EFR32_HFRCO_MAX_FREQ (38000000UL)
58 #endif
59
60 #ifndef EFR32_HFXO_FREQ
61 /** HFXO frequency */
62 #define EFR32_HFXO_FREQ (38400000UL)
63 #endif
64
65 #ifndef EFR32_HFRCO_STARTUP_FREQ
66 /** HFRCO startup frequency */
67 #define EFR32_HFRCO_STARTUP_FREQ (19000000UL)
68 #endif
69
70 /* Do not define variable if HF crystal oscillator not present */
71 #if (EFR32_HFXO_FREQ > 0U)
72 /** @cond DO_NOT_INCLUDE_WITH_DOXYGEN */
73 /** System HFXO clock. */
74 static uint32_t SystemHFXOClock = EFR32_HFXO_FREQ;
75 /** @endcond (DO_NOT_INCLUDE_WITH_DOXYGEN) */
76 #endif
77
78 #ifndef EFR32_LFXO_FREQ
79 /** LFXO frequency */
80 #define EFR32_LFXO_FREQ (EFR32_LFRCO_FREQ)
81 #endif
82 /* Do not define variable if LF crystal oscillator not present */
83 #if (EFR32_LFXO_FREQ > 0U)
84 /** @cond DO_NOT_INCLUDE_WITH_DOXYGEN */
85 /** System LFXO clock. */
86 static uint32_t SystemLFXOClock = EFR32_LFXO_FREQ;
87 /** @endcond (DO_NOT_INCLUDE_WITH_DOXYGEN) */
88 #endif
89
90 /*******************************************************************************
91 ************************** GLOBAL VARIABLES *******************************
92 ******************************************************************************/
93
94 /**
95 * @brief
96 * System System Clock Frequency (Core Clock).
97 *
98 * @details
99 * Required CMSIS global variable that must be kept up-to-date.
100 */
101 uint32_t SystemCoreClock = EFR32_HFRCO_STARTUP_FREQ;
102
103 /**
104 * @brief
105 * System HFRCO frequency
106 *
107 * @note
108 * This is an EFR32 proprietary variable, not part of the CMSIS definition.
109 *
110 * @details
111 * Frequency of the system HFRCO oscillator
112 */
113 uint32_t SystemHfrcoFreq = EFR32_HFRCO_STARTUP_FREQ;
114
115 /*******************************************************************************
116 ************************** GLOBAL FUNCTIONS *******************************
117 ******************************************************************************/
118
119 /***************************************************************************//**
120 * @brief
121 * Get the current core clock frequency.
122 *
123 * @details
124 * Calculate and get the current core clock frequency based on the current
125 * configuration. Assuming that the SystemCoreClock global variable is
126 * maintained, the core clock frequency is stored in that variable as well.
127 * This function will however calculate the core clock based on actual HW
128 * configuration. It will also update the SystemCoreClock global variable.
129 *
130 * @note
131 * This is an EFR32 proprietary function, not part of the CMSIS definition.
132 *
133 * @return
134 * The current core clock frequency in Hz.
135 ******************************************************************************/
SystemCoreClockGet(void)136 uint32_t SystemCoreClockGet(void)
137 {
138 uint32_t ret;
139 uint32_t presc;
140
141 ret = SystemHFClockGet();
142 presc = (CMU->HFCOREPRESC & _CMU_HFCOREPRESC_PRESC_MASK)
143 >> _CMU_HFCOREPRESC_PRESC_SHIFT;
144 ret /= presc + 1U;
145
146 /* Keep CMSIS system clock variable up-to-date */
147 SystemCoreClock = ret;
148
149 return ret;
150 }
151
152 /***************************************************************************//**
153 * @brief
154 * Get the maximum core clock frequency.
155 *
156 * @note
157 * This is an EFR32 proprietary function, not part of the CMSIS definition.
158 *
159 * @return
160 * The maximum core clock frequency in Hz.
161 ******************************************************************************/
SystemMaxCoreClockGet(void)162 uint32_t SystemMaxCoreClockGet(void)
163 {
164 #if (EFR32_HFRCO_MAX_FREQ > EFR32_HFXO_FREQ)
165 return EFR32_HFRCO_MAX_FREQ;
166 #else
167 return EFR32_HFXO_FREQ;
168 #endif
169 }
170
171 /***************************************************************************//**
172 * @brief
173 * Get the current HFCLK frequency.
174 *
175 * @note
176 * This is an EFR proprietary function, not part of the CMSIS definition.
177 *
178 * @return
179 * The current HFCLK frequency in Hz.
180 ******************************************************************************/
SystemHFClockGet(void)181 uint32_t SystemHFClockGet(void)
182 {
183 uint32_t ret;
184
185 switch (CMU->HFCLKSTATUS & _CMU_HFCLKSTATUS_SELECTED_MASK) {
186 case CMU_HFCLKSTATUS_SELECTED_LFXO:
187 #if (EFR32_LFXO_FREQ > 0U)
188 ret = SystemLFXOClock;
189 #else
190 /* We should not get here, since core should not be clocked. May */
191 /* be caused by a misconfiguration though. */
192 ret = 0U;
193 #endif
194 break;
195
196 case CMU_HFCLKSTATUS_SELECTED_LFRCO:
197 ret = EFR32_LFRCO_FREQ;
198 break;
199
200 case CMU_HFCLKSTATUS_SELECTED_HFXO:
201 #if (EFR32_HFXO_FREQ > 0U)
202 ret = SystemHFXOClock;
203 #else
204 /* We should not get here, since core should not be clocked. May */
205 /* be caused by a misconfiguration though. */
206 ret = 0U;
207 #endif
208 break;
209
210 case CMU_HFCLKSTATUS_SELECTED_HFRCODIV2:
211 ret = SystemHfrcoFreq / 2;
212 break;
213
214 default: /* CMU_HFCLKSTATUS_SELECTED_HFRCO */
215 ret = SystemHfrcoFreq;
216 break;
217 }
218
219 return ret / (1U + ((CMU->HFPRESC & _CMU_HFPRESC_PRESC_MASK)
220 >> _CMU_HFPRESC_PRESC_SHIFT));
221 }
222
223 /***************************************************************************//**
224 * @brief
225 * Get high frequency crystal oscillator clock frequency for target system.
226 *
227 * @note
228 * This is an EFR proprietary function, not part of the CMSIS definition.
229 *
230 * @return
231 * HFXO frequency in Hz.
232 ******************************************************************************/
SystemHFXOClockGet(void)233 uint32_t SystemHFXOClockGet(void)
234 {
235 /* External crystal oscillator present? */
236 #if (EFR32_HFXO_FREQ > 0U)
237 return SystemHFXOClock;
238 #else
239 return 0U;
240 #endif
241 }
242
243 /***************************************************************************//**
244 * @brief
245 * Set high frequency crystal oscillator clock frequency for target system.
246 *
247 * @note
248 * This function is mainly provided for being able to handle target systems
249 * with different HF crystal oscillator frequencies run-time. If used, it
250 * should probably only be used once during system startup.
251 *
252 * @note
253 * This is an EFR proprietary function, not part of the CMSIS definition.
254 *
255 * @param[in] freq
256 * HFXO frequency in Hz used for target.
257 ******************************************************************************/
SystemHFXOClockSet(uint32_t freq)258 void SystemHFXOClockSet(uint32_t freq)
259 {
260 /* External crystal oscillator present? */
261 #if (EFR32_HFXO_FREQ > 0U)
262 SystemHFXOClock = freq;
263
264 /* Update core clock frequency if HFXO is used to clock core */
265 if ((CMU->HFCLKSTATUS & _CMU_HFCLKSTATUS_SELECTED_MASK)
266 == CMU_HFCLKSTATUS_SELECTED_HFXO) {
267 /* The function will update the global variable */
268 (void)SystemCoreClockGet();
269 }
270 #else
271 (void)freq; /* Unused parameter */
272 #endif
273 }
274
275 /***************************************************************************//**
276 * @brief
277 * Initialize the system.
278 *
279 * @details
280 * Do required generic HW system init.
281 *
282 * @note
283 * This function is invoked during system init, before the main() routine
284 * and any data has been initialized. For this reason, it cannot do any
285 * initialization of variables etc.
286 ******************************************************************************/
SystemInit(void)287 void SystemInit(void)
288 {
289 #if defined(__VTOR_PRESENT) && (__VTOR_PRESENT == 1U)
290 SCB->VTOR = (uint32_t)&__Vectors;
291 #endif
292
293 #if (__FPU_PRESENT == 1U) && (__FPU_USED == 1U)
294 /* Set floating point coprosessor access mode. */
295 SCB->CPACR |= ((3UL << 10 * 2) /* set CP10 Full Access */
296 | (3UL << 11 * 2)); /* set CP11 Full Access */
297 #endif
298
299 #if defined(UNALIGNED_SUPPORT_DISABLE)
300 SCB->CCR |= SCB_CCR_UNALIGN_TRP_Msk;
301 #endif
302 }
303
304 /***************************************************************************//**
305 * @brief
306 * Get low frequency RC oscillator clock frequency for target system.
307 *
308 * @note
309 * This is an EFR proprietary function, not part of the CMSIS definition.
310 *
311 * @return
312 * LFRCO frequency in Hz.
313 ******************************************************************************/
SystemLFRCOClockGet(void)314 uint32_t SystemLFRCOClockGet(void)
315 {
316 /* Currently we assume that this frequency is properly tuned during */
317 /* manufacturing and is not changed after reset. If future requirements */
318 /* for re-tuning by user, we can add support for that. */
319 return EFR32_LFRCO_FREQ;
320 }
321
322 /***************************************************************************//**
323 * @brief
324 * Get ultra low frequency RC oscillator clock frequency for target system.
325 *
326 * @note
327 * This is an EFR proprietary function, not part of the CMSIS definition.
328 *
329 * @return
330 * ULFRCO frequency in Hz.
331 ******************************************************************************/
SystemULFRCOClockGet(void)332 uint32_t SystemULFRCOClockGet(void)
333 {
334 /* The ULFRCO frequency is not tuned, and can be very inaccurate */
335 return EFR32_ULFRCO_FREQ;
336 }
337
338 /***************************************************************************//**
339 * @brief
340 * Get low frequency crystal oscillator clock frequency for target system.
341 *
342 * @note
343 * This is an EFR proprietary function, not part of the CMSIS definition.
344 *
345 * @return
346 * LFXO frequency in Hz.
347 ******************************************************************************/
SystemLFXOClockGet(void)348 uint32_t SystemLFXOClockGet(void)
349 {
350 /* External crystal oscillator present? */
351 #if (EFR32_LFXO_FREQ > 0U)
352 return SystemLFXOClock;
353 #else
354 return 0U;
355 #endif
356 }
357
358 /***************************************************************************//**
359 * @brief
360 * Set low frequency crystal oscillator clock frequency for target system.
361 *
362 * @note
363 * This function is mainly provided for being able to handle target systems
364 * with different HF crystal oscillator frequencies run-time. If used, it
365 * should probably only be used once during system startup.
366 *
367 * @note
368 * This is an EFR proprietary function, not part of the CMSIS definition.
369 *
370 * @param[in] freq
371 * LFXO frequency in Hz used for target.
372 ******************************************************************************/
SystemLFXOClockSet(uint32_t freq)373 void SystemLFXOClockSet(uint32_t freq)
374 {
375 /* External crystal oscillator present? */
376 #if (EFR32_LFXO_FREQ > 0U)
377 SystemLFXOClock = freq;
378
379 /* Update core clock frequency if LFXO is used to clock core */
380 if ((CMU->HFCLKSTATUS & _CMU_HFCLKSTATUS_SELECTED_MASK)
381 == CMU_HFCLKSTATUS_SELECTED_LFXO) {
382 /* The function will update the global variable */
383 (void)SystemCoreClockGet();
384 }
385 #else
386 (void)freq; /* Unused parameter */
387 #endif
388 }
389
