1 /***************************************************************************//**
2 * @file
3 * @brief CMSIS Cortex-M4 System Layer for EFM32 devices.
4 *******************************************************************************
5 * # License
6 * <b>Copyright 2022 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 EFM32_LFRCO_FREQ (32768UL)
40 /** ULFRCO frequency */
41 #define EFM32_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 EFM32_nFXO_FREQ */
51 /* values according to board design. By defining the EFM32_nFXO_FREQ to 0, */
52 /* one indicates that the oscillator is not present, in order to save some */
53 /* SW footprint. */
54
55 #ifndef EFM32_HFRCO_MAX_FREQ
56 /** Maximum HFRCO frequency */
57 #define EFM32_HFRCO_MAX_FREQ (72000000UL)
58 #endif
59
60 #ifndef EFM32_HFXO_FREQ
61 /** HFXO frequency */
62 #define EFM32_HFXO_FREQ (50000000UL)
63 #endif
64
65 #ifndef EFM32_HFRCO_STARTUP_FREQ
66 /** HFRCO startup frequency */
67 #define EFM32_HFRCO_STARTUP_FREQ (19000000UL)
68 #endif
69
70 /* Do not define variable if HF crystal oscillator not present */
71 #if (EFM32_HFXO_FREQ > 0U)
72 /** @cond DO_NOT_INCLUDE_WITH_DOXYGEN */
73 /** System HFXO clock. */
74 static uint32_t SystemHFXOClock = EFM32_HFXO_FREQ;
75 /** @endcond (DO_NOT_INCLUDE_WITH_DOXYGEN) */
76 #endif
77
78 #ifndef EFM32_LFXO_FREQ
79 /** LFXO frequency */
80 #define EFM32_LFXO_FREQ (EFM32_LFRCO_FREQ)
81 #endif
82 /* Do not define variable if LF crystal oscillator not present */
83 #if (EFM32_LFXO_FREQ > 0U)
84 /** @cond DO_NOT_INCLUDE_WITH_DOXYGEN */
85 /** System LFXO clock. */
86 static uint32_t SystemLFXOClock = EFM32_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 = EFM32_HFRCO_STARTUP_FREQ;
102
103 /**
104 * @brief
105 * System HFRCO frequency
106 *
107 * @note
108 * This is an EFM32 proprietary variable, not part of the CMSIS definition.
109 *
110 * @details
111 * Frequency of the system HFRCO oscillator
112 */
113 uint32_t SystemHfrcoFreq = EFM32_HFRCO_STARTUP_FREQ;
114
115 /*---------------------------------------------------------------------------
116 Exception / Interrupt Vector table
117 *---------------------------------------------------------------------------*/
118 extern const tVectorEntry __VECTOR_TABLE[16 + EXT_IRQ_COUNT];
119
120 /*******************************************************************************
121 ************************** GLOBAL FUNCTIONS *******************************
122 ******************************************************************************/
123
124 /***************************************************************************//**
125 * @brief
126 * Get the current core clock frequency.
127 *
128 * @details
129 * Calculate and get the current core clock frequency based on the current
130 * configuration. Assuming that the SystemCoreClock global variable is
131 * maintained, the core clock frequency is stored in that variable as well.
132 * This function will however calculate the core clock based on actual HW
133 * configuration. It will also update the SystemCoreClock global variable.
134 *
135 * @note
136 * This is an EFM32 proprietary function, not part of the CMSIS definition.
137 *
138 * @return
139 * The current core clock frequency in Hz.
140 ******************************************************************************/
SystemCoreClockGet(void)141 uint32_t SystemCoreClockGet(void)
142 {
143 uint32_t ret;
144 uint32_t presc;
145
146 ret = SystemHFClockGet();
147 presc = (CMU->HFCOREPRESC & _CMU_HFCOREPRESC_PRESC_MASK)
148 >> _CMU_HFCOREPRESC_PRESC_SHIFT;
149 ret /= presc + 1U;
150
151 /* Keep CMSIS system clock variable up-to-date */
152 SystemCoreClock = ret;
153
154 return ret;
155 }
156
157 /***************************************************************************//**
158 * @brief
159 * Get the maximum core clock frequency.
160 *
161 * @note
162 * This is an EFM32 proprietary function, not part of the CMSIS definition.
163 *
164 * @return
165 * The maximum core clock frequency in Hz.
166 ******************************************************************************/
SystemMaxCoreClockGet(void)167 uint32_t SystemMaxCoreClockGet(void)
168 {
169 #if (EFM32_HFRCO_MAX_FREQ > EFM32_HFXO_FREQ)
170 return EFM32_HFRCO_MAX_FREQ;
171 #else
172 return EFM32_HFXO_FREQ;
173 #endif
174 }
175
176 /***************************************************************************//**
177 * @brief
178 * Get the current HFCLK frequency.
179 *
180 * @note
181 * This is an EFM32 proprietary function, not part of the CMSIS definition.
182 *
183 * @return
184 * The current HFCLK frequency in Hz.
185 ******************************************************************************/
SystemHFClockGet(void)186 uint32_t SystemHFClockGet(void)
187 {
188 uint32_t ret;
189
190 switch (CMU->HFCLKSTATUS & _CMU_HFCLKSTATUS_SELECTED_MASK) {
191 case CMU_HFCLKSTATUS_SELECTED_LFXO:
192 #if (EFM32_LFXO_FREQ > 0U)
193 ret = SystemLFXOClock;
194 #else
195 /* We should not get here, since core should not be clocked. May */
196 /* be caused by a misconfiguration though. */
197 ret = 0U;
198 #endif
199 break;
200
201 case CMU_HFCLKSTATUS_SELECTED_LFRCO:
202 ret = EFM32_LFRCO_FREQ;
203 break;
204
205 case CMU_HFCLKSTATUS_SELECTED_HFXO:
206 #if (EFM32_HFXO_FREQ > 0U)
207 ret = SystemHFXOClock;
208 #else
209 /* We should not get here, since core should not be clocked. May */
210 /* be caused by a misconfiguration though. */
211 ret = 0U;
212 #endif
213 break;
214
215 case CMU_HFCLKSTATUS_SELECTED_USHFRCO:
216 switch ((CMU->USHFRCOCTRL & _CMU_USHFRCOCTRL_FREQRANGE_MASK)
217 >> _CMU_USHFRCOCTRL_FREQRANGE_SHIFT) {
218 case 7:
219 ret = 16000000U;
220 break;
221 case 11:
222 ret = 32000000U;
223 break;
224 case 13:
225 ret = 48000000U;
226 break;
227 case 14:
228 ret = 50000000U;
229 break;
230 default:
231 ret = 0U;
232 break;
233 }
234 break;
235
236 case CMU_HFCLKSTATUS_SELECTED_HFRCODIV2:
237 ret = SystemHfrcoFreq / 2;
238 break;
239
240 default: /* CMU_HFCLKSTATUS_SELECTED_HFRCO */
241 ret = SystemHfrcoFreq;
242 break;
243 }
244
245 return ret / (1U + ((CMU->HFPRESC & _CMU_HFPRESC_PRESC_MASK)
246 >> _CMU_HFPRESC_PRESC_SHIFT));
247 }
248
249 /***************************************************************************//**
250 * @brief
251 * Get high frequency crystal oscillator clock frequency for target system.
252 *
253 * @note
254 * This is an EFM32 proprietary function, not part of the CMSIS definition.
255 *
256 * @return
257 * HFXO frequency in Hz.
258 ******************************************************************************/
SystemHFXOClockGet(void)259 uint32_t SystemHFXOClockGet(void)
260 {
261 /* External crystal oscillator present? */
262 #if (EFM32_HFXO_FREQ > 0U)
263 return SystemHFXOClock;
264 #else
265 return 0U;
266 #endif
267 }
268
269 /***************************************************************************//**
270 * @brief
271 * Set high frequency crystal oscillator clock frequency for target system.
272 *
273 * @note
274 * This function is mainly provided for being able to handle target systems
275 * with different HF crystal oscillator frequencies run-time. If used, it
276 * should probably only be used once during system startup.
277 *
278 * @note
279 * This is an EFM32 proprietary function, not part of the CMSIS definition.
280 *
281 * @param[in] freq
282 * HFXO frequency in Hz used for target.
283 ******************************************************************************/
SystemHFXOClockSet(uint32_t freq)284 void SystemHFXOClockSet(uint32_t freq)
285 {
286 /* External crystal oscillator present? */
287 #if (EFM32_HFXO_FREQ > 0U)
288 SystemHFXOClock = freq;
289
290 /* Update core clock frequency if HFXO is used to clock core */
291 if ((CMU->HFCLKSTATUS & _CMU_HFCLKSTATUS_SELECTED_MASK)
292 == CMU_HFCLKSTATUS_SELECTED_HFXO) {
293 /* The function will update the global variable */
294 (void)SystemCoreClockGet();
295 }
296 #else
297 (void)freq; /* Unused parameter */
298 #endif
299 }
300
301 /***************************************************************************//**
302 * @brief
303 * Initialize the system.
304 *
305 * @details
306 * Do required generic HW system init.
307 *
308 * @note
309 * This function is invoked during system init, before the main() routine
310 * and any data has been initialized. For this reason, it cannot do any
311 * initialization of variables etc.
312 ******************************************************************************/
SystemInit(void)313 void SystemInit(void)
314 {
315 #if defined (__VTOR_PRESENT) && (__VTOR_PRESENT == 1U)
316 SCB->VTOR = (uint32_t)(&__VECTOR_TABLE[0]);
317 #endif
318
319 #if (__FPU_PRESENT == 1U) && (__FPU_USED == 1U)
320 /* Set floating point coprosessor access mode. */
321 SCB->CPACR |= ((3UL << 10 * 2) /* set CP10 Full Access */
322 | (3UL << 11 * 2)); /* set CP11 Full Access */
323 #endif
324
325 #if defined(UNALIGNED_SUPPORT_DISABLE)
326 SCB->CCR |= SCB_CCR_UNALIGN_TRP_Msk;
327 #endif
328 }
329
330 /***************************************************************************//**
331 * @brief
332 * Get low frequency RC oscillator clock frequency for target system.
333 *
334 * @note
335 * This is an EFM32 proprietary function, not part of the CMSIS definition.
336 *
337 * @return
338 * LFRCO frequency in Hz.
339 ******************************************************************************/
SystemLFRCOClockGet(void)340 uint32_t SystemLFRCOClockGet(void)
341 {
342 /* Currently we assume that this frequency is properly tuned during */
343 /* manufacturing and is not changed after reset. If future requirements */
344 /* for re-tuning by user, we can add support for that. */
345 return EFM32_LFRCO_FREQ;
346 }
347
348 /***************************************************************************//**
349 * @brief
350 * Get ultra low frequency RC oscillator clock frequency for target system.
351 *
352 * @note
353 * This is an EFM32 proprietary function, not part of the CMSIS definition.
354 *
355 * @return
356 * ULFRCO frequency in Hz.
357 ******************************************************************************/
SystemULFRCOClockGet(void)358 uint32_t SystemULFRCOClockGet(void)
359 {
360 /* The ULFRCO frequency is not tuned, and can be very inaccurate */
361 return EFM32_ULFRCO_FREQ;
362 }
363
364 /***************************************************************************//**
365 * @brief
366 * Get low frequency crystal oscillator clock frequency for target system.
367 *
368 * @note
369 * This is an EFM32 proprietary function, not part of the CMSIS definition.
370 *
371 * @return
372 * LFXO frequency in Hz.
373 ******************************************************************************/
SystemLFXOClockGet(void)374 uint32_t SystemLFXOClockGet(void)
375 {
376 /* External crystal oscillator present? */
377 #if (EFM32_LFXO_FREQ > 0U)
378 return SystemLFXOClock;
379 #else
380 return 0U;
381 #endif
382 }
383
384 /***************************************************************************//**
385 * @brief
386 * Set low frequency crystal oscillator clock frequency for target system.
387 *
388 * @note
389 * This function is mainly provided for being able to handle target systems
390 * with different HF crystal oscillator frequencies run-time. If used, it
391 * should probably only be used once during system startup.
392 *
393 * @note
394 * This is an EFM32 proprietary function, not part of the CMSIS definition.
395 *
396 * @param[in] freq
397 * LFXO frequency in Hz used for target.
398 ******************************************************************************/
SystemLFXOClockSet(uint32_t freq)399 void SystemLFXOClockSet(uint32_t freq)
400 {
401 /* External crystal oscillator present? */
402 #if (EFM32_LFXO_FREQ > 0U)
403 SystemLFXOClock = freq;
404
405 /* Update core clock frequency if LFXO is used to clock core */
406 if ((CMU->HFCLKSTATUS & _CMU_HFCLKSTATUS_SELECTED_MASK)
407 == CMU_HFCLKSTATUS_SELECTED_LFXO) {
408 /* The function will update the global variable */
409 (void)SystemCoreClockGet();
410 }
411 #else
412 (void)freq; /* Unused parameter */
413 #endif
414 }
415
