1 /***************************************************************************//**
2 * @file
3 * @brief CMSIS Cortex-M0+ System Layer for EFM32HG 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 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_HFXO_FREQ
56 /** HFXO frequency. */
57 #define EFM32_HFXO_FREQ (24000000UL)
58 #endif
59
60 /** Maximum HFRCO frequency. */
61 #define EFM32_HFRCO_MAX_FREQ (21000000UL)
62
63 /* Do not define variable if HF crystal oscillator not present */
64 #if (EFM32_HFXO_FREQ > 0U)
65 /** @cond DO_NOT_INCLUDE_WITH_DOXYGEN */
66 /** System HFXO clock. */
67 static uint32_t SystemHFXOClock = EFM32_HFXO_FREQ;
68 /** @endcond (DO_NOT_INCLUDE_WITH_DOXYGEN) */
69 #endif
70
71 #ifndef EFM32_LFXO_FREQ
72 /** LFXO frequency. */
73 #define EFM32_LFXO_FREQ (EFM32_LFRCO_FREQ)
74 #endif
75
76 /* Do not define variable if LF crystal oscillator not present */
77 #if (EFM32_LFXO_FREQ > 0U)
78 /** @cond DO_NOT_INCLUDE_WITH_DOXYGEN */
79 /** System LFXO clock. */
80 static uint32_t SystemLFXOClock = EFM32_LFXO_FREQ;
81 /** @endcond (DO_NOT_INCLUDE_WITH_DOXYGEN) */
82 #endif
83
84 /*******************************************************************************
85 ************************** GLOBAL VARIABLES *******************************
86 ******************************************************************************/
87
88 /**
89 * @brief
90 * System System Clock Frequency (Core Clock).
91 *
92 * @details
93 * Required CMSIS global variable that must be kept up-to-date.
94 */
95 uint32_t SystemCoreClock = 14000000UL;
96
97 /*******************************************************************************
98 ************************** GLOBAL FUNCTIONS *******************************
99 ******************************************************************************/
100
101 /***************************************************************************//**
102 * @brief
103 * Get the current core clock frequency.
104 *
105 * @details
106 * Calculate and get the current core clock frequency based on the current
107 * configuration. Assuming that the SystemCoreClock global variable is
108 * maintained, the core clock frequency is stored in that variable as well.
109 * This function will however calculate the core clock based on actual HW
110 * configuration. It will also update the SystemCoreClock global variable.
111 *
112 * @note
113 * This is an EFM32 proprietary function, not part of the CMSIS definition.
114 *
115 * @return
116 * The current core clock frequency in Hz.
117 ******************************************************************************/
SystemCoreClockGet(void)118 uint32_t SystemCoreClockGet(void)
119 {
120 uint32_t ret;
121
122 ret = SystemHFClockGet();
123 ret >>= (CMU->HFCORECLKDIV & _CMU_HFCORECLKDIV_HFCORECLKDIV_MASK)
124 >> _CMU_HFCORECLKDIV_HFCORECLKDIV_SHIFT;
125
126 /* Keep CMSIS variable up-to-date just in case */
127 SystemCoreClock = ret;
128
129 return ret;
130 }
131
132 /***************************************************************************//**
133 * @brief
134 * Get the maximum core clock frequency.
135 *
136 * @note
137 * This is an EFM32 proprietary function, not part of the CMSIS definition.
138 *
139 * @return
140 * The maximum core clock frequency in Hz.
141 ******************************************************************************/
SystemMaxCoreClockGet(void)142 uint32_t SystemMaxCoreClockGet(void)
143 {
144 #if (EFM32_HFRCO_MAX_FREQ > EFM32_HFXO_FREQ)
145 return EFM32_HFRCO_MAX_FREQ;
146 #else
147 return EFM32_HFXO_FREQ;
148 #endif
149 }
150
151 /***************************************************************************//**
152 * @brief
153 * Get the current HFCLK frequency.
154 *
155 * @note
156 * This is an EFM32 proprietary function, not part of the CMSIS definition.
157 *
158 * @return
159 * The current HFCLK frequency in Hz.
160 ******************************************************************************/
SystemHFClockGet(void)161 uint32_t SystemHFClockGet(void)
162 {
163 uint32_t ret;
164
165 switch (CMU->STATUS & (CMU_STATUS_HFRCOSEL | CMU_STATUS_HFXOSEL
166 | CMU_STATUS_LFRCOSEL | CMU_STATUS_LFXOSEL
167 #if defined(CMU_STATUS_USHFRCODIV2SEL)
168 | CMU_STATUS_USHFRCODIV2SEL
169 #endif
170 )) {
171 case CMU_STATUS_LFXOSEL:
172 #if (EFM32_LFXO_FREQ > 0U)
173 ret = SystemLFXOClock;
174 #else
175 /* We should not get here, since core should not be clocked. May */
176 /* be caused by a misconfiguration though. */
177 ret = 0U;
178 #endif
179 break;
180
181 case CMU_STATUS_LFRCOSEL:
182 ret = EFM32_LFRCO_FREQ;
183 break;
184
185 case CMU_STATUS_HFXOSEL:
186 #if (EFM32_HFXO_FREQ > 0U)
187 ret = SystemHFXOClock;
188 #else
189 /* We should not get here, since core should not be clocked. May */
190 /* be caused by a misconfiguration though. */
191 ret = 0U;
192 #endif
193 break;
194
195 #if defined(CMU_STATUS_USHFRCODIV2SEL)
196 case CMU_STATUS_USHFRCODIV2SEL:
197 ret = 24000000U;
198 break;
199 #endif
200
201 default: /* CMU_STATUS_HFRCOSEL */
202 switch (CMU->HFRCOCTRL & _CMU_HFRCOCTRL_BAND_MASK) {
203 case CMU_HFRCOCTRL_BAND_21MHZ:
204 ret = 21000000U;
205 break;
206
207 case CMU_HFRCOCTRL_BAND_14MHZ:
208 ret = 14000000U;
209 break;
210
211 case CMU_HFRCOCTRL_BAND_11MHZ:
212 ret = 11000000U;
213 break;
214
215 case CMU_HFRCOCTRL_BAND_7MHZ:
216 ret = 6600000U;
217 break;
218
219 case CMU_HFRCOCTRL_BAND_1MHZ:
220 ret = 1200000U;
221 break;
222
223 default:
224 ret = 0U;
225 break;
226 }
227 break;
228 }
229
230 return ret / (1U + ((CMU->CTRL & _CMU_CTRL_HFCLKDIV_MASK)
231 >> _CMU_CTRL_HFCLKDIV_SHIFT));
232 }
233
234 /***************************************************************************//**
235 * @brief
236 * Get high frequency crystal oscillator clock frequency for target system.
237 *
238 * @note
239 * This is an EFM32 proprietary function, not part of the CMSIS definition.
240 *
241 * @return
242 * HFXO frequency in Hz.
243 ******************************************************************************/
SystemHFXOClockGet(void)244 uint32_t SystemHFXOClockGet(void)
245 {
246 /* External crystal oscillator present? */
247 #if (EFM32_HFXO_FREQ > 0U)
248 return SystemHFXOClock;
249 #else
250 return 0U;
251 #endif
252 }
253
254 /***************************************************************************//**
255 * @brief
256 * Set high frequency crystal oscillator clock frequency for target system.
257 *
258 * @note
259 * This function is mainly provided for being able to handle target systems
260 * with different HF crystal oscillator frequencies run-time. If used, it
261 * should probably only be used once during system startup.
262 *
263 * @note
264 * This is an EFM32 proprietary function, not part of the CMSIS definition.
265 *
266 * @param[in] freq
267 * HFXO frequency in Hz used for target.
268 ******************************************************************************/
SystemHFXOClockSet(uint32_t freq)269 void SystemHFXOClockSet(uint32_t freq)
270 {
271 /* External crystal oscillator present? */
272 #if (EFM32_HFXO_FREQ > 0U)
273 SystemHFXOClock = freq;
274
275 /* Update core clock frequency if HFXO is used to clock core */
276 if ((CMU->STATUS & CMU_STATUS_HFXOSEL) != 0U) {
277 /* The function will update the global variable */
278 (void)SystemCoreClockGet();
279 }
280 #else
281 (void)freq; /* Unused parameter */
282 #endif
283 }
284
285 /***************************************************************************//**
286 * @brief
287 * Initialize the system.
288 *
289 * @details
290 * Do required generic HW system init.
291 *
292 * @note
293 * This function is invoked during system init, before the main() routine
294 * and any data has been initialized. For this reason, it cannot do any
295 * initialization of variables etc.
296 ******************************************************************************/
SystemInit(void)297 void SystemInit(void)
298 {
299 #if defined(__VTOR_PRESENT) && (__VTOR_PRESENT == 1U)
300 SCB->VTOR = (uint32_t)&__Vectors;
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 EFM32 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 EFM32_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 EFM32 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 EFM32_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 EFM32 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 (EFM32_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 EFM32 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 (EFM32_LFXO_FREQ > 0U)
377 SystemLFXOClock = freq;
378
379 /* Update core clock frequency if LFXO is used to clock core */
380 if ((CMU->STATUS & CMU_STATUS_LFXOSEL) != 0U) {
381 /* The function will update the global variable */
382 (void)SystemCoreClockGet();
383 }
384 #else
385 (void)freq; /* Unused parameter */
386 #endif
387 }
388
