1.. zephyr:board:: weact_stm32g431_core
2
3The WeAct STM32G431 Core Board is a low-cost bare-bones STM32G431-based development
4board. See the `STM32G431CB website`_ for more information about the MCU. More information
5about the board, including schematics, is available from the `WeAct GitHub`_.
6
7Modifications USB-C Power Delivery
8**********************************
9
10The board does not support USB-C PD in its standard configuration. To enable USB-C PD, CC1
11and CC2 need to be disconnected from their pull-down resistors and be connected to PB6 and
12PB4 respectively. Dead battery support requires PA9 and PA10 to be routed to CC1 and
13CC2. VBUS also needs to be connected to the MCU through a voltage divider.
14
15The pull-downs are disconnected by removing the zero-Ohm resistors on SB8 and SB9 next to
16the USB-C connector. SB3, SB5, SB6, and SB7 then need to be closed to connect the CCx
17lines to the MCU. The voltage divider is connected to PB2 by closing SB4.
18
19After these modifications have been made, PA9, PA10, PB2, PB4, and PB6 should be
20considered reserved for USB-C and not available for other applications.
21
22.. warning::
23   The internal USB DFU boot loader may not work correctly with machines that respect USB
24   PD signaling unless dead battery support has been enabled. A USB-C to USB-A adapter or
25   programming using the SWD port can be used as a workaround.
26
27
28Supported Features
29==================
30
31The Zephyr weact_stm32g431_core board configuration supports the following hardware
32features:
33
34+------------+------------+-------------------------------------+
35| Interface  | Controller | Driver/Component                    |
36+============+============+=====================================+
37| NVIC       | on-chip    | nested vector interrupt controller  |
38+------------+------------+-------------------------------------+
39| UART       | on-chip    | serial port                         |
40+------------+------------+-------------------------------------+
41| GPIO       | on-chip    | gpio                                |
42+------------+------------+-------------------------------------+
43| ADC        | on-chip    | ADC Controller                      |
44+------------+------------+-------------------------------------+
45| USB        | on-chip    | USB device                          |
46+------------+------------+-------------------------------------+
47| UCPD       | on-chip    | ucpd                                |
48+------------+------------+-------------------------------------+
49
50The default configuration can be found in the defconfig file:
51
52:zephyr_file:`boards/weact/stm32g431_core/weact_stm32g431_core_defconfig`
53
54Pin Mapping
55===========
56
57Default Zephyr Peripheral Mapping:
58----------------------------------
59
60- UART_2 TX/RX   : PA2/PA3
61- UCPD1 CCx      : PB6/PB4 (not connected by default)
62- UCPD1 DBCCx    : PA9/PA10 (not connected by default)
63- BUTTON (User)  : PC13
64- BUTTON (BOOT0) : PB8
65- LED0           : PC6
66- ADC (VBUS)     : PB2
67
68The ADC is disabled by default since the VBUS voltage divider is not connected in the
69board's standard configuration.
70
71
72Hardware Configuration
73----------------------
74+---------------+---------+-----------------------------------------------+
75| Solder bridge | Default | Description                                   |
76+===============+=========+===============================================+
77| SB1/SB2       | Open    | Route PC14/PC15 (LSE) to header               |
78+---------------+---------+-----------------------------------------------+
79| SB6/SB7       | Open    | Connect PB4/PB6 (UCPD1_CCx) to USB-C CCx pins |
80+---------------+---------+-----------------------------------------------+
81| SB3/SB5       | Open    | Connect PA9/PA10 (UCPD1_DBCCx) to PB6/PB4     |
82+---------------+---------+-----------------------------------------------+
83| SB4           | Open    | Connect PB2 to VBUS voltage divider           |
84+---------------+---------+-----------------------------------------------+
85| SB8/SB9       | Closed  | Connect USB-CCx to pull-down resistors        |
86+---------------+---------+-----------------------------------------------+
87| SB10          | Open    | VBUS protection diode bypass                  |
88+---------------+---------+-----------------------------------------------+
89
90
91Clock Sources
92-------------
93
94The board has two external oscillators. The frequency of the slow clock (LSE) is 32.768
95kHz. The frequency of the main clock (HSE) is 8 MHz.
96
97The default configuration sources the system clock from the PLL, which is derived from
98HSE, and is set at 144 MHz. The 48 MHz clock used by the USB interface is derived from the
99PLL instead of the internal 48 MHz oscillator.
100
101Programming and Debugging
102*************************
103
104The MCU is normally programmed using the ROM bootloader or the exposed SWD port.
105
106Please note that some laptops may not detect the ROM bootloader correctly if the CCx
107pull-downs have been disconnected by opening SB8 and SB9 unless dead battery support has
108been enabled by closing SB3 and SB5. A USB-C to USB-A adapter can be used as a workaround
109if this is a problem.
110
111Flashing an Application
112=======================
113
114Connect a USB-C cable and the board should power ON. Force the board into DFU mode by
115keeping the BOOT0 switch pressed while pressing and releasing the NRST switch.
116
117The dfu-util runner is supported on this board and so a sample can be built and tested
118easily.
119
120.. zephyr-app-commands::
121   :zephyr-app: samples/basic/blinky
122   :board: weact_stm32g431_core
123   :goals: build flash
124
125Debugging
126=========
127
128The board can be debugged by installing the included 100 mil (0.1 inch) header, and
129attaching an SWD debugger to the 3V3 (3.3V), GND, SCK, and DIO pins on that header.
130
131
132References
133**********
134
135.. target-notes::
136
137.. _WeAct GitHub:
138   https://github.com/WeActStudio/WeActStudio.STM32G431CoreBoard
139
140.. _STM32G431CB website:
141   https://www.st.com/en/microcontrollers-microprocessors/stm32g431cb.html
142
143.. _STM32F401x reference manual:
144   https://www.st.com/resource/en/reference_manual/rm0440-stm32g4-series-advanced-armbased-32bit-mcus-stmicroelectronics.pdf
145