system_stm32l4xx.c
13.3 KB
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
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
/**
******************************************************************************
* @file system_stm32l4xx.c
* @author MCD Application Team
* @brief CMSIS Cortex-M4 Device Peripheral Access Layer System Source File
*
* This file provides two functions and one global variable to be called from
* user application:
* - SystemInit(): This function is called at startup just after reset and
* before branch to main program. This call is made inside
* the "startup_stm32l4xx.s" file.
*
* - SystemCoreClock variable: Contains the core clock (HCLK), it can be used
* by the user application to setup the SysTick
* timer or configure other parameters.
*
* - SystemCoreClockUpdate(): Updates the variable SystemCoreClock and must
* be called whenever the core clock is changed
* during program execution.
*
* After each device reset the MSI (4 MHz) is used as system clock source.
* Then SystemInit() function is called, in "startup_stm32l4xx.s" file, to
* configure the system clock before to branch to main program.
*
* This file configures the system clock as follows:
*=============================================================================
*-----------------------------------------------------------------------------
* System Clock source | MSI
*-----------------------------------------------------------------------------
* SYSCLK(Hz) | 4000000
*-----------------------------------------------------------------------------
* HCLK(Hz) | 4000000
*-----------------------------------------------------------------------------
* AHB Prescaler | 1
*-----------------------------------------------------------------------------
* APB1 Prescaler | 1
*-----------------------------------------------------------------------------
* APB2 Prescaler | 1
*-----------------------------------------------------------------------------
* PLL_M | 1
*-----------------------------------------------------------------------------
* PLL_N | 8
*-----------------------------------------------------------------------------
* PLL_P | 7
*-----------------------------------------------------------------------------
* PLL_Q | 2
*-----------------------------------------------------------------------------
* PLL_R | 2
*-----------------------------------------------------------------------------
* PLLSAI1_P | NA
*-----------------------------------------------------------------------------
* PLLSAI1_Q | NA
*-----------------------------------------------------------------------------
* PLLSAI1_R | NA
*-----------------------------------------------------------------------------
* PLLSAI2_P | NA
*-----------------------------------------------------------------------------
* PLLSAI2_Q | NA
*-----------------------------------------------------------------------------
* PLLSAI2_R | NA
*-----------------------------------------------------------------------------
* Require 48MHz for USB OTG FS, | Disabled
* SDIO and RNG clock |
*-----------------------------------------------------------------------------
*=============================================================================
******************************************************************************
* @attention
*
* <h2><center>© COPYRIGHT(c) 2017 STMicroelectronics</center></h2>
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. Neither the name of STMicroelectronics nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
******************************************************************************
*/
/** @addtogroup CMSIS
* @{
*/
/** @addtogroup stm32l4xx_system
* @{
*/
/** @addtogroup STM32L4xx_System_Private_Includes
* @{
*/
#include "stm32l4xx.h"
#if !defined (HSE_VALUE)
#define HSE_VALUE 8000000U /*!< Value of the External oscillator in Hz */
#endif /* HSE_VALUE */
#if !defined (MSI_VALUE)
#define MSI_VALUE 4000000U /*!< Value of the Internal oscillator in Hz*/
#endif /* MSI_VALUE */
#if !defined (HSI_VALUE)
#define HSI_VALUE 16000000U /*!< Value of the Internal oscillator in Hz*/
#endif /* HSI_VALUE */
/**
* @}
*/
/** @addtogroup STM32L4xx_System_Private_TypesDefinitions
* @{
*/
/**
* @}
*/
/** @addtogroup STM32L4xx_System_Private_Defines
* @{
*/
/************************* Miscellaneous Configuration ************************/
/*!< Uncomment the following line if you need to relocate your vector Table in
Internal SRAM. */
/* #define VECT_TAB_SRAM */
#define VECT_TAB_OFFSET 0x00 /*!< Vector Table base offset field.
This value must be a multiple of 0x200. */
/******************************************************************************/
/**
* @}
*/
/** @addtogroup STM32L4xx_System_Private_Macros
* @{
*/
/**
* @}
*/
/** @addtogroup STM32L4xx_System_Private_Variables
* @{
*/
/* The SystemCoreClock variable is updated in three ways:
1) by calling CMSIS function SystemCoreClockUpdate()
2) by calling HAL API function HAL_RCC_GetHCLKFreq()
3) each time HAL_RCC_ClockConfig() is called to configure the system clock frequency
Note: If you use this function to configure the system clock; then there
is no need to call the 2 first functions listed above, since SystemCoreClock
variable is updated automatically.
*/
uint32_t SystemCoreClock = 4000000U;
const uint8_t AHBPrescTable[16] = {0U, 0U, 0U, 0U, 0U, 0U, 0U, 0U, 1U, 2U, 3U, 4U, 6U, 7U, 8U, 9U};
const uint8_t APBPrescTable[8] = {0U, 0U, 0U, 0U, 1U, 2U, 3U, 4U};
const uint32_t MSIRangeTable[12] = {100000U, 200000U, 400000U, 800000U, 1000000U, 2000000U, \
4000000U, 8000000U, 16000000U, 24000000U, 32000000U, 48000000U};
/**
* @}
*/
/** @addtogroup STM32L4xx_System_Private_FunctionPrototypes
* @{
*/
/**
* @}
*/
/** @addtogroup STM32L4xx_System_Private_Functions
* @{
*/
/**
* @brief Setup the microcontroller system.
* @param None
* @retval None
*/
void SystemInit(void)
{
/* FPU settings ------------------------------------------------------------*/
#if (__FPU_PRESENT == 1) && (__FPU_USED == 1)
SCB->CPACR |= ((3UL << 10*2)|(3UL << 11*2)); /* set CP10 and CP11 Full Access */
#endif
/* Reset the RCC clock configuration to the default reset state ------------*/
/* Set MSION bit */
RCC->CR |= RCC_CR_MSION;
/* Reset CFGR register */
RCC->CFGR = 0x00000000U;
/* Reset HSEON, CSSON , HSION, and PLLON bits */
RCC->CR &= 0xEAF6FFFFU;
/* Reset PLLCFGR register */
RCC->PLLCFGR = 0x00001000U;
/* Reset HSEBYP bit */
RCC->CR &= 0xFFFBFFFFU;
/* Disable all interrupts */
RCC->CIER = 0x00000000U;
/* Configure the Vector Table location add offset address ------------------*/
#ifdef VECT_TAB_SRAM
SCB->VTOR = SRAM_BASE | VECT_TAB_OFFSET; /* Vector Table Relocation in Internal SRAM */
#else
SCB->VTOR = FLASH_BASE | VECT_TAB_OFFSET; /* Vector Table Relocation in Internal FLASH */
#endif
}
/**
* @brief Update SystemCoreClock variable according to Clock Register Values.
* The SystemCoreClock variable contains the core clock (HCLK), it can
* be used by the user application to setup the SysTick timer or configure
* other parameters.
*
* @note Each time the core clock (HCLK) changes, this function must be called
* to update SystemCoreClock variable value. Otherwise, any configuration
* based on this variable will be incorrect.
*
* @note - The system frequency computed by this function is not the real
* frequency in the chip. It is calculated based on the predefined
* constant and the selected clock source:
*
* - If SYSCLK source is MSI, SystemCoreClock will contain the MSI_VALUE(*)
*
* - If SYSCLK source is HSI, SystemCoreClock will contain the HSI_VALUE(**)
*
* - If SYSCLK source is HSE, SystemCoreClock will contain the HSE_VALUE(***)
*
* - If SYSCLK source is PLL, SystemCoreClock will contain the HSE_VALUE(***)
* or HSI_VALUE(*) or MSI_VALUE(*) multiplied/divided by the PLL factors.
*
* (*) MSI_VALUE is a constant defined in stm32l4xx_hal.h file (default value
* 4 MHz) but the real value may vary depending on the variations
* in voltage and temperature.
*
* (**) HSI_VALUE is a constant defined in stm32l4xx_hal.h file (default value
* 16 MHz) but the real value may vary depending on the variations
* in voltage and temperature.
*
* (***) HSE_VALUE is a constant defined in stm32l4xx_hal.h file (default value
* 8 MHz), user has to ensure that HSE_VALUE is same as the real
* frequency of the crystal used. Otherwise, this function may
* have wrong result.
*
* - The result of this function could be not correct when using fractional
* value for HSE crystal.
*
* @param None
* @retval None
*/
void SystemCoreClockUpdate(void)
{
uint32_t tmp = 0U, msirange = 0U, pllvco = 0U, pllr = 2U, pllsource = 0U, pllm = 2U;
/* Get MSI Range frequency--------------------------------------------------*/
if((RCC->CR & RCC_CR_MSIRGSEL) == RESET)
{ /* MSISRANGE from RCC_CSR applies */
msirange = (RCC->CSR & RCC_CSR_MSISRANGE) >> 8U;
}
else
{ /* MSIRANGE from RCC_CR applies */
msirange = (RCC->CR & RCC_CR_MSIRANGE) >> 4U;
}
/*MSI frequency range in HZ*/
msirange = MSIRangeTable[msirange];
/* Get SYSCLK source -------------------------------------------------------*/
switch (RCC->CFGR & RCC_CFGR_SWS)
{
case 0x00: /* MSI used as system clock source */
SystemCoreClock = msirange;
break;
case 0x04: /* HSI used as system clock source */
SystemCoreClock = HSI_VALUE;
break;
case 0x08: /* HSE used as system clock source */
SystemCoreClock = HSE_VALUE;
break;
case 0x0C: /* PLL used as system clock source */
/* PLL_VCO = (HSE_VALUE or HSI_VALUE or MSI_VALUE/ PLLM) * PLLN
SYSCLK = PLL_VCO / PLLR
*/
pllsource = (RCC->PLLCFGR & RCC_PLLCFGR_PLLSRC);
pllm = ((RCC->PLLCFGR & RCC_PLLCFGR_PLLM) >> 4U) + 1U ;
switch (pllsource)
{
case 0x02: /* HSI used as PLL clock source */
pllvco = (HSI_VALUE / pllm);
break;
case 0x03: /* HSE used as PLL clock source */
pllvco = (HSE_VALUE / pllm);
break;
default: /* MSI used as PLL clock source */
pllvco = (msirange / pllm);
break;
}
pllvco = pllvco * ((RCC->PLLCFGR & RCC_PLLCFGR_PLLN) >> 8U);
pllr = (((RCC->PLLCFGR & RCC_PLLCFGR_PLLR) >> 25U) + 1U) * 2U;
SystemCoreClock = pllvco/pllr;
break;
default:
SystemCoreClock = msirange;
break;
}
/* Compute HCLK clock frequency --------------------------------------------*/
/* Get HCLK prescaler */
tmp = AHBPrescTable[((RCC->CFGR & RCC_CFGR_HPRE) >> 4U)];
/* HCLK clock frequency */
SystemCoreClock >>= tmp;
}
/**
* @}
*/
/**
* @}
*/
/**
* @}
*/
/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/