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
|
/**
@page PWR_SMPS_16MHZ_HSI PWR SMPS example
@verbatim
******************************************************************************
* @file Examples_LL/PWR/PWR_SMPS_16MHZ_HSI/readme.txt
* @author MCD Application Team
* @brief Description of the PWR SMPS example.
******************************************************************************
*
* Copyright (c) 2019-2021 STMicroelectronics.
* All rights reserved.
*
* This software is licensed under terms that can be found in the LICENSE file
* in the root directory of this software component.
* If no LICENSE file comes with this software, it is provided AS-IS.
*
******************************************************************************
@endverbatim
@par Example Description
This example shows how to use power converters of STM32WB (SMPS, LDO and LP-LDO)
depending on Vdd voltage and low-power mode.
User can act on 2 parameters to use power converters of STM32WB:
- Usage of SMPS or LDO:
Caution: BOR level must be set to level 1, 2, 3 or 4 (not level 0, default configuration)
The recommended BOR level is level 1: BOR1 voltage rising edge 2.1V, falling edge 2.0V (refer to device datasheet for more information).
To change BOR level, use tool ST-Link utility to update option bytes.
User must apply a variation of Vdd: Remove jumper JP2 and supply JP2 pin "VDD" by an external voltage.
This is the use case, for example , of a battery voltage variation depending on lifetime or current load.
- If Vdd > BOR level: Vcore is supplied by SMPS + LDO
SMPS is in mode step-down and is converting power for the main LDO.
The transition of SMPS mode bypass to step-down is not done automatically by HW. This example performs it by SW.
LED2 toggles at fast speed (2.5Hz).
- If Vdd < BOR level: Vcore is supplied by LDO
SMPS is in mode bypass, Vdd is connected directly to the main LDO.
The transition of SMPS mode step-down to bypass is done automaticcaly by HW.
LED2 toggles at slow speed (1Hz).
- Usage of LP-LDO:
User must make the device enter in low-power mode standby: enter in standby with push button (through pin PC.04), exit from stanby with LL_PWR_WAKEUP_PIN2 on pin PC13 or with button RESET.
- If device enters in low-power mode:
Vcore is supplied by LP-LDO (Vdd is connected directly to the LP-LDO)
If SMPS was in mode step-down, then it is switching to mode open to preserve energy stored in decoupling capacitor.
Note: Other low-power modes that can use LP-LDO: stop1, stop2, standy, shutdown
LED2 is turned off.
- If device exit from low-power mode:
Vcore is supplied by SMPS+LDO or LDO (refer to case above).
LED2 is turned on during 1 second (to indicate wake-up from low-power), then toggles at speed depending on SMPS mode.
This example has configuration option, selected with literals:
- RF stack configuration: RF_STACK_AVAILABLE
Refer to comments inlined in code for their usage.
@note When Vdd voltage is low, LED2 luminosity is low and can appear as turned-off.
In this case, to monitor LED2 toggling frequency, an oscilloscope should be used.
@note Wake-up pin connection: On board STM32WB Nucleo64, pin PC13 is not connected to user button by default, solder bridge SB48 must be closed.
Alternate solution: connect a wire between PC4 (pin connected to user button) and PC13.
@note To measure MCU current consumption on board STM32WB Nucleo,
board configuration must be applied:
- remove all jumpers on connector JP5 to avoid leakages between ST-Link circuitry and STM32WB device.
- remove jumper JP2 and connect an amperemeter to measure current between the 2 connectors of JP2.
@note This example can not be used in DEBUG mode due to the fact
that the Cortex-M4 core is no longer clocked during low power mode
so debugging features are disabled.
@par Keywords
PWR, SMPS, step-down
@par Directory contents
- PWR/PWR_SMPS_16MHZ_HSI/Inc/stm32wbxx_it.h Interrupt handlers header file
- PWR/PWR_SMPS_16MHZ_HSI/Inc/main.h Header for main.c module
- PWR/PWR_SMPS_16MHZ_HSI/Inc/stm32_assert.h Template file to include assert_failed function
- PWR/PWR_SMPS_16MHZ_HSI/Src/stm32wbxx_it.c Interrupt handlers
- PWR/PWR_SMPS_16MHZ_HSI/Src/main.c Main program
- PWR/PWR_SMPS_16MHZ_HSI/Src/system_stm32wbxx.c STM32WBxx system source file
@par Hardware and Software environment
- This example runs on STM32WB55xx devices.
- This example has been tested with STMicroelectronics P-NUCLEO-WB55
board and can be easily tailored to any other supported device
and development board.
@par How to use it ?
In order to make the program work, you must do the following :
- Open your preferred toolchain
- Rebuild all files and load your image into target memory
- Run the example
* <h3><center>© COPYRIGHT STMicroelectronics</center></h3>
*/
|
