Hardware Connection

Top-Side Interfaces

• Type-C connector for power and USB debug
• SD card slot
• Reset button
• Snapshot button
• UART debug header (STM32N6)
• ST-Link header (STM32N6)
• ST-Link header (STM32U0)
• ST BOOT mode selector
• Alarm input terminal
• USB camera / PIR connector
• Dual CV light-board headers
• OS04C10 camera connector
• Battery isolation slide switch

Bottom-Side Interfaces

• Power input terminals
• Expansion IO headers (SPI, I2C, UART, GPIO, and power rails)

Interface Details

Peripheral Power Control — STM32N657L0H3

Enable the following rails before using their peripherals: raise CAM_PWR for the camera & fill light, TF_PWR_ON for the TF card, BAT_DEF_ON for battery sensing, and PWR_USB_3.3V for USB data.

Pin	Signal	MCU Pin	Type	Default State	Alt
T2	CAM_PWR	PF9	I/O	Pulldown 100 KΩ	—
W12	TF_PWR_ON	PA1	I/O	Pulldown 100 KΩ	—
T8	BAT_DEF_ON	PA11	I/O	Pulldown 100 KΩ	—
W11	PWR_USB_3.3V	PG13	I/O	—	—

RS485 Control — STM32N657L0H3

Set RS485_RE#/RS485_DE high or low to switch TX/RX direction. Leave them tristated when unused.

Pin	Signal	MCU Pin	Type	Default	Alt
A18	RS485_USART3_RX	PE0	I/O	—	USART3_RX
B17	RS485_RE#	PB3	I/O	—	—
B18	RS485_USART3_TX	PE1	I/O	—	USART3_TX
B19	RS485_DE	PE2	I/O	—	—

Camera Interface

The OS04C10 uses a CSI-2 interface. Pull CAM_PWR high before use.

Pin	Signal	Function	Type	Default	Alt
1	GND	Ground	—	—	—
2	CSI_D0N	CSI_D0N	Input	—	—
3	CSI_D0P	CSI_D0P	Input	—	—
4	GND	Ground	—	—	—
5	CSI_D1N	CSI_D1N	Input	—	—
6	CSI_D1P	CSI_D1P	Input	—	—
7	GND	Ground	—	—	—
8	CSI_CKN	CSI clock-	Input	—	—
9	CSI_CKP	CSI clock+	Input	—	—
10	GND	Ground	—	—	—
11	CSI_EN	PG0	I/O	—	—
12	CSI_CLK	PA8	I/O	—	—
13	CSI_I3C2_SCL	PB10	I/O	Pull-up 4.7 KΩ	—
14	CSI_I3C2_SDA	PB11	I/O	Pull-up 4.7 KΩ	—
15	3V3_CSI	3.3 V	—	—	—

Fill-Light Control — STM32N657L0H3

Set CAM_PWR high before toggling the PWM LED.

Pin	Signal	MCU Pin	Type	Default	Alt
R2	PWM_LED	PF7	I/O	Pulldown 100 KΩ	TIM3_CH3

Indicator LEDs — STM32N657L0H3

U0_PWR_3V3 must be high and STM32N6 must be running.

Pin	Signal	MCU Pin	Type	Default	Alt
P1	LIGHT_RESISTOR	PF3	I/O	Pulldown 51 KΩ	—
V16	PWR_LED1	PG9	I/O	—	—
T12	DEBUG_LED	PG10	I/O	—	—

TF Card Interface — STM32N657L0H3

Raise TF_PWR_ON before accessing the TF card.

Pin	Signal	MCU Pin	Type	Default	Alt
1	SDIO_TF_D2	PC10	I/O	Pull-up 10 KΩ	—
2	SDIO_TF_D3	PC11	I/O	Pull-up 10 KΩ	—
3	SDIO_TF_CMD	PH2	I/O	Pull-up 10 KΩ	—
4	SDIO_TF_CK	PC12	I/O	Pull-up 10 KΩ	—
5	SDIO_TF_D0	PC8	I/O	Pull-up 10 KΩ	—
6	SDIO_TF_D1	PC9	I/O	Pull-up 10 KΩ	—
7	SDIO_TF_INT	PD0	I/O	Pull-up 1 MΩ	—

Wi-Fi Chip Interface — STM32N657L0H3

Pin	Signal	MCU Pin	Type	Default	Alt
D10	SPI4_SCK	PE12	I/O	Pull-up 10 KΩ	—
D8	SPI4_NSS	PE11	I/O	Pull-up 10 KΩ	—
E16	SPI4_MOSI	PB7	I/O	—	—
D19	SPI4_MISO	PB6	I/O	—	—
A13	WIFI_SPI4_IRQ	PE8	I/O	—	—
A15	WIFI_SleepMode_STA	PD5	I/O	—	—
A11	WIFI_ULP_WAKEUP	PD12	I/O	—	—
A17	WIFI_RESET_N	PD11	I/O	Pull-up 100 KΩ	—
A14	WIFI_POC_IN	PB15	I/O	—	—
B15	N6_PWR_WIFI	PB9	I/O	Pulldown 100 KΩ	—

External PSRAM — STM32N657L0H3

Pin	Signal	MCU Pin	Type
H18	XSPIM_P1_IO0	PP0	I/O
F18	XSPIM_P1_IO1	PP1	I/O
K18	XSPIM_P1_IO2	PP2	I/O
K19	XSPIM_P1_IO3	PP3	I/O
L19	XSPIM_P1_IO4	PP4	I/O
J19	XSPIM_P1_IO5	PP5	I/O
H19	XSPIM_P1_IO6	PP6	I/O
G19	XSPIM_P1_IO7	PP7	I/O
F19	XSPIM_P1_IO8	PP8	I/O
E19	XSPIM_P1_IO9	PP9	I/O
D18	XSPIM_P1_IO10	PP10	I/O
N19	XSPIM_P1_IO11	PP11	I/O
N18	XSPIM_P1_IO12	PP12	I/O
M19	XSPIM_P1_IO13	PP13	I/O
M18	XSPIM_P1_IO14	PP14	I/O
L18	XSPIM_P1_IO15	PP15	I/O
F16	XSPIM_P1_NCS1	PO0	I/O
G18	XSPIM_P1_DQS0	PO2	I/O
E18	XSPIM_P1_DQS1	PO3	I/O
J18	XSPIM_P1_CLK	PO4	I/O

External Flash — STM32N657L0H3

Pin	Signal	MCU Pin	Type
R19	XSPIM_P2_DQS0	PN0	I/O
P16	XSPIM_P2_NCS1	PN1	I/O
T19	XSPIM_P2_IO0	PN2	I/O
P19	XSPIM_P2_IO1	PN3	I/O
V19	XSPIM_P2_IO2	PN4	I/O
U18	XSPIM_P2_IO3	PN5	I/O
U19	XSPIM_P2_CLK	PN6	I/O
V18	XSPIM_P2_IO4	PN8	I/O
T18	XSPIM_P2_IO5	PN9	I/O
R18	XSPIM_P2_IO6	PN10	I/O
P18	XSPIM_P2_IO7	PN11	I/O

Reset Button — STM32N657L0H3

Pin	Signal	MCU Pin	Type	Default
F2	NRST	NRST	Input	Pull-up 47 KΩ

UART Debug Header (J26) — STM32N657L0H3

Pin	Signal	MCU Pin	Type	Default
1	3V3	—	Supply	—
2	USART2_RX	PA2	I/O	Pull-up 10 KΩ
3	USART2_TX	PF6	I/O	Pull-up 10 KΩ
4	GND	—	Supply	—

ST-Link Header — STM32N657L0H3

Pin	Signal	MCU Pin	Type
1	VCC_IN	—	Supply
2	SWDIO	PA13	I/O
3	SWCLK	PA14	I/O
4	GND	—	Supply

BOOT Mode Selector — STM32N657L0H3

Pin	Signal	MCU Pin	Type	Default
F4	BOOT0	BOOT0	Input	Pulldown 1 MΩ
T10	BOOT1	PA6	I/O	Pulldown 1 MΩ

External Oscillators — STM32N657L0H3

Pin	Signal	MCU Pin	Type
A5	HSE_OSC_IN	PH0-OSC_IN	I/O
B5	HSE_OSC_OUT	PH1-OSC_OUT	I/O
D1	N6_32.768KHZ_P	PC15-OSC32_OUT	I/O
E1	N6_32.768KHZ_N	PC14-OSC32_IN	I/O

STM32U073KBU6 Link

Pin	Signal	MCU Pin	Type	Default
U1	UART9_RX	PF1	I/O	Pull-up 10 KΩ
U3	UART9_TX	PF0	I/O	Pull-up 10 KΩ

Communication Module Headers

Expansion modules mount on J11/J15. J12, J15, and J11 pinouts are listed below.

16-pin Expansion Header (J12)

Provides UART, I2C, SPI, RS485, etc., for sensor modules such as PIR or OLED.

Pin	Signal	MCU Pin	Type	Default	Alt
1	RS485_B	—	—	—	—
2	GND	—	Supply	—	—
3	RS485_A	—	—	—	—
4	GND	—	Supply	—	—
5	PD8_TAMP	PD8	I/O	—	—
6	5V0_POE	Power-In	Supply	—	—
7	SPI2_MISO	PD6	I/O	—	—
8	VCC_3V3	Power-Out	Supply	—	—
9	SPI2_SCK	PF2	I/O	Pull-up 10 KΩ	—
10	PF4_ADC	PF4	I/O	—	ADC_INP18
11	SPI2_MOSI	PD2	I/O	—	—
12	SPI2_NSS	PB12	I/O	—	—
13	I2C2_SCL	PD14	I/O	Pull-up 4.7 KΩ	—
14	LPUART1_TX	PA9	I/O	—	—
15	I2C2_SDA	PD15	I/O	Pull-up 4.7 KΩ	—
16	LPUART1_RX	PA10	I/O	—	—

VCC_3V3 Control (STM32N657L0H3): Set PWR_VCC_EXT high to enable the 3.3 V rail.

Pin	Signal	MCU Pin	Type	Default
M2	PWR_VCC_EXT	PF10	I/O	Pulldown 100 KΩ

12-pin Module Header (J15)

Pin	Signal	MCU Pin	Type	Default
1	CAT1_MAIN_IR	PA2 (U0)	I/O	—
2	3V3_VDD0	—	Supply	—
3	GND	—	Supply	—
4	GND	—	Supply	—
5	I2C1_SCL	PE5	I/O	Pull-up 10 KΩ
6	I2C1_SDA	PE6	I/O	Pull-up 10 KΩ
7	SAI1_FS_B	PG1	I/O	—
8	SAI1_MCLK_B	PG12	I/O	—
9	SAI1_SD_B	PA3	I/O	—
10	SAI1_SCK_B	PG0	I/O	—
11	OTG2_HSDP	OTG2_HSDP	I/O	—
12	OTG2_HSDM	OTG2_HSDM	I/O	—

3V3_VDD0 Control (STM32N657L0H3): Raise PWR_VDD0 to enable.

Pin	Signal	MCU Pin	Type	Default
P2	PWR_VDD0	PF14	I/O	Pulldown 100 KΩ

16-pin Module Header (J11)

Pin	Signal	MCU Pin	Type	Default	Alt
1	VCC_IN	—	Supply	—	—
2	3V3	—	Supply	—	—
3	VCC_IN	—	Supply	—	—
4	3V3	—	Supply	—	—
5	CAT1_PWR_ON (Halow Wi-Fi)	PG8	I/O	—	—
6	GND	—	Supply	—	—
7	Halow SPI6_MOSI	PA7	I/O	—	—
8	Halow SPI6_MISO	PB4	I/O	—	—
9	CAT1_UART7_RX	PG11	I/O	Pull-up 10 KΩ	—
10	Halow SPI6_NSS	PA0	I/O	—	ADC_INP18
11	CAT1_UART7_TX	PA15	I/O	—	—
12	Halow_IRQ	PA4	I/O	—	—
13	GND	—	I/O	Pull-up 4.7 KΩ	—
14	SAI1_SD_A (Wi-Fi wake)	PB2	I/O	—	—
15	Halow SPI6_SCK	PA5	I/O	Pull-up 4.7 KΩ	—
16	Halow_RST	PB0	I/O	—	—

3.3 V Output Control — STM32U073KBU6: Raise U0_PWR_3V3 to enable.

Pin	Signal	MCU Pin	Type	Default
11	PWR_VDD0	PA5	I/O	Pulldown 100 KΩ

Trigger Button — STM32U073KBU6

Pin	Signal	MCU Pin	Type	Default
6	U0_CONFIG	PA0-CK_IN	I/O	Pull-up 47 KΩ

STM32N6 ↔ STM32U0 Link

Pin	Signal	MCU Pin	Type
29	U0_LPUART2_TX	PB6	I/O
30	U0_LPUART2_RX	PB7	I/O

Control & Trigger Pins — STM32U073KBU6

Pin	Signal	MCU Pin	Type	Default
8	CAT1_MAIN_IR	PA2	I/O	—
10	U0_PWR_WIFI	PA4	I/O	Pulldown 100 KΩ
11	U0_PWR_3V3	PA5	I/O	Pulldown 100 KΩ
12	U0_PWR_AON	PA6	I/O	Pulldown 100 KΩ
13	U0_PWR_N6	PA7	I/O	Pulldown 100 KΩ
14	CAT1_PWR_ON (Halow Wi-Fi)	PB0	I/O	—
15	U0_RST_N6	PB1	I/O	Pull-up 47 KΩ
18	TEST_USB_IN	PA8	I/O	—
21	WIFI_SPI4_IRQ	PA1 / PA9	I/O	—

PIR Sensor Header — STM32U073KBU6

Pin	Signal	Description	Type
1	VDD	Supply	Supply
2	GND	Ground	Supply
3	Serial_IN	PA3	I/O
4	INT/Dout	PA1	I/O