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CM5 Core Board – Pinout

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CM5 Core Board — Technical Manual

1. Food #

The information below is limited to the key points to avoid any ambiguity.

Signal / Element Value Description
Main entrance 5 V Main power supply for the board
GPIO logic level 3.3 V Logic voltage of GPIO interfaces
GPIO Compatibility 3.3 V only The GPIOs are not 5 V-tolerant
Never apply a 5 V signal directly to a GPIO pin. Use a level shifter if an external interface operates at 5 V.

2. Auxiliary connectors #

The following tables describe only the signals explicitly mentioned in the original document.

USB Sync Camera — 5-pin #

Pine Signal Description
1 +5 V Food
2 USB D− USB data line
3 USB D+ USB data line
4 GND Mass
5 FSYNC Camera synchronization
FSYNC — Multi-camera synchronization (DWE Machine Vision)

The signal FSYNC enables precise synchronization of multiple cameras to ensure temporal alignment of images, which is essential for applications such as stereo vision, 3D reconstruction, or object tracking.
Supported synchronization methods:
  • Leader/Follower Mode:
    One camera is configured as the Leader and generates a synchronization signal that is distributed to the other cameras configured as Followers.
  • Follower-only mode (external clock):
    All cameras are configured in Follower mode and use an external signal (microcontroller, PWM generator) as a common reference.
How it works:
  • The cameras start recording when they detect the FSYNC signal
  • The signal frequency determines the frame rate (FPS)
  • All cameras must share the same time reference
Recommendations:
  • Standardized mass required for all equipment
  • Limit the length of connections to reduce jitter
  • Adjust the FSYNC signal frequency to the desired frame rate
Reference: DWE Machine Vision Documentation — Multi-Camera Synchronization

Auxiliary I²C — 4-pin #

Pine Signal Description
1 +3.3 V Sensor power supply
2 SCL I²C Clock
3 SDA I²C data
4 GND Mass

SPI Display — 10-pin #

Pine Signal Description
1 +3.3 V_PI Display power supply
2 GND Mass
3 DC Data / Command
4 RST Reset
5 CS Chip Select
6 GND Mass
7 Backlight Backlight Control
8 SCLK SPI Clock
9 MOSI SPI data
10 MISO SPI data

Control connectors #

Connector Pine Signal Description
Day 8 (RGB) 1 +5V LED power supply
2 GPIO18 Signal data (WS2812 / NeoPixel)
3 GND Mass
J601 (FAN) 1 +5V Fan power supply
2 PWM Speed control
3 Tach RPM (tachometer)
4 GND Mass
CN1 (PSTN) 1 +BATT RTC battery input
2 GND Mass
Day 9 (SW) 1 nGLOBAL_EN Power-on command
2 GND Mass

HDMI Interface #

The board features an HDMI output that allows video to be displayed directly from the Compute Module 5.

Setting Value Description
Connector type HDMI Digital video output
Source 5th Grade Signal generated by the Compute Module
Audio Supported Audio transmission via HDMI
Hot-plug Yes Automatic screen detection
The HDMI output settings (resolution, rotation, primary display) are controlled by the system via configuration files (/boot/firmware/config.txt).

USB-C / USB Device & System Provisioning #

The USB-C port provides power to the board and allows access to the Compute Module 5 in peripheral mode for system booting.

Setting Value Description
Connector type USB-C Power and Data Interface
USB Mode USB Device (OTG) Connecting to a PC for programming
Function Stocking Booting the system from eMMC
Compatible tools rpiboot / Raspberry Pi Imager CM5 Flash Utilities
The USB-C port can be used as the primary power source when the card is used without a power daughter card.
Verify that the power supplied via USB-C is sufficient for the application, especially when external devices (SSD, USB, camera) are connected.

Selecting the boot mode #

Switch position Signal Fashion Description
runOS nRPIBOOT = HIGH Normal startup Boots from eMMC or NVMe, depending on the configuration
nRPIBOOT nRPIBOOT = LOW Programming mode Enabling USB flash mode for the system
The runOS | nRPIBOOT switch allows you to select the boot mode for the Compute Module 5 before powering it on.
In nRPIBOOT mode, the module is detected as a USB device by a host computer, allowing the system image to be written directly using tools such as rpiboot.
The switch must be switched off before changing its position. Any changes made after startup will have no effect.

3. 40-pin GPIO #

Connector compatible with the Raspberry Pi ecosystem. The GPIO pins operate at 3.3 V.

Pine Signal Description
13.3VFood
25VFood
3GPIO2 / SDA1I²C
45VFood
5GPIO3 / SCL1I²C
6GNDMass
7GPIO4GPIO
8GPIO14 / TXDUART
9GNDMass
10GPIO15 / RXDUART
11GPIO17GPIO
12GPIO18GPIO / PWM
13GPIO27GPIO
14GNDMass
15GPIO22GPIO
16GPIO23GPIO
173.3VFood
18GPIO24GPIO
19GPIO10 / MOSISPI
20GNDMass
21GPIO9 / MISOSPI
22GPIO25GPIO
23GPIO11 / SCLKSPI
24GPIO8 / CE0SPI
25GNDMass
26GPIO7 / CE1SPI
27ID_SDEEPROM HAT
28ID_SCEEPROM HAT
29GPIO5GPIO
30GNDMass
31GPIO6GPIO
32GPIO12GPIO / PWM
33GPIO13GPIO / PWM
34GNDMass
35GPIO19GPIO / SPI
36GPIO16GPIO
37GPIO26GPIO
38GPIO20GPIO / SPI
39GNDMass
40GPIO21GPIO / SPI
The presence of an alternative function on a GPIO does not necessarily mean that it is used in your application. Refer to the software configuration for the actual pin assignments.

5. Storage #

The card includes an M.2 slot for NVMe storage.

Setting Value Description
Interface PCIe Gen 2 x1 Main interface for NVMe SSDs
Format 2230 / 2242 Mechanical formats supported by the designated slot
Mechanical wrench Key-M NVMe Compatibility

4. RTC battery and power-on control #

RTC #

Element Value Description
Connector CN1 RTC battery input
Pins +BATT / GND PSTN connection

Powering on #

Element Value Description
Connector J9 External control
Signal nGLOBAL_EN Power control signal
Reference GND Mass

5. Precautions #

Turn off the power before connecting or disconnecting sensitive devices, particularly camera interfaces, GPIO connectors, and ribbon cables.
When interfacing with external equipment, verify the compatibility of logic levels, ground connections, and power supplies before turning on the power.

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