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CM5-ETH-RS485-4G-BASE

CM5-ETH-RS485-4G-BASE

The CM5-ETH-RS485-4G-BASE is a base board for the Raspberry Pi Compute Module 5. It offers powerful features, including 1x USB 3.2 Gen1, 1x USB2.0, M.2 M KEY, M.2 B KEY (for 4G/5G modules), and dual Ethernet ports, with additional GPIO‑expanded RS485, digital input, and relay for user convenience.

SKUProduct
34251CM5-ETH-RS485-4G-BASE
34402CM5-ETH-RS485-4G-BOX (US)
34403CM5-ETH-RS485-4G-BOX (EU)
34404CM5-ETH-RS485-4G-BOX (UK)

Version Options​

Dual Gigabit Ethernet CM5 Expansion Board
(Base board)

Dual Gigabit Ethernet CM5 Host
(Base board + metal case)

Features​

  • Do not plug or unplug any devices other than USB and HDMI while the system is powered on
  • The Type-C port can be used as a USB SLAVE interface for flashing images or powering the device
  • Onboard 1 USB port group with a total maximum output current of 2A (1x USB 3.2 Gen1 + 1x USB 2.0 port)
  • Supports triple independent displays. When a MIPI DSI driver is added, the system will default to connecting to it regardless of whether a screen is connected, and the screen will display in split-screen mode (depending on the system version)
  • Onboard M.2 M KEY interface, supports NVMe SSD protocol (or PCIe protocol AI modules).
  • Onboard M.2 B KEY interface, supports 4G/5G communication modules
  • 4 isolated RS485 channels + 1 isolated digital input + 1 isolated relay (fully isolated)
  • Onboard encryption chip and single controllable buzzer
  • Onboard BOOT button: Press and hold the BOOT button before powering on, then connect to a PC via Type-C to enter flashing mode
  • When using Type‑C for programming, do not connect any other devices, otherwise insufficient power may prevent the device from being recognized

Onboard Resources​

1. CM5 Socket
Compatible with all versions of Compute Module 5
2. Nano SIM Card Slot
3. TF Card Slot
For connecting a TF card with an OS system (Applicable only for CM5 versions without eMMC)
4. Fan Interface Y
Supports 2242 / 2230 NVMe SSDs or AI modules
5. Flashing Interface
Used for eMMC flashing or USB OTG
6. HDMI Interface
Supports 4K output
7. Button & LED Expansion Interface
8. Dual USB Ports
One standard USB 2.0 port and one USB 3.2 Gen1 port (USB 3.2 Gen1 supports up to 5Gbps)
9. 1000M Ethernet Port
RJ45 1000M port, supports 10M / 100M / 1000M network connections
10. 2500M Ethernet Port
RJ45 2500M port, supports 10M / 100M / 1000M / 2500M network connections
11. Indicator LEDs
Status LEDs for various interfaces, plus two extra user‑configurable LEDs
12. M.2 M KEY
Supports 2242 / 2230 NVMe SSDs or AI modules
13. M.2 B KEY
Supports 4G / 5G communication modules
14. Buzzer
15. DC Power Supply Jack
Supports DC 7V ~ 36V power input (do not connect power simultaneously with the screw terminal)
16. DC Power Screw Terminal
Supports DC 7V ~ 36V power input (do not connect power simultaneously with the DC power supply jack)
17. RS485 Interfaces
18. Digital Input Interface
Input voltage: 5V ~ 36V
19. Relay Interface
Contact rating: ≤ 10A 250V AC or ≤ 10A 30V DC
20. RTC Battery Header
Accepts a compatible RTC battery to power the RTC
21. Encryption Chip
22. Dual MIPI Interfaces
Supports connecting DSI displays or CSI cameras. The case only has a cutout for MIPI0; MIPI1 cannot be routed outside the case.
23. BOOT Button
Set to ON before power‑up; the board will enter programming mode on power‑up

Dimensions​

Image Flashing​

  • Entering Download Mode
    • Onboard BOOT switch: slide the BOOT switch to ON before power‑up, then connect the board to a computer via Type‑C; it will enter programming mode
  • Flashing Images for LITE Versions: LITE Version Tutorial
  • Flashing Images for EMMC Versions: EMMC Version Tutorial

NVMe(M.2 M KEY)​

NVMe SSD Boot​

  • First, boot the Raspberry Pi using a TF card, mount and test the NVMe SSD to ensure the hardware functions correctly
  • NVMe SSD Boot: Boot Configuration Tutorial

MIPI​

warning

The case only has a cutout for MIPI0; MIPI1 cannot be routed outside the case. MIPI1 can only be used when the case is not assembled.

Fan Control​

RTC​

RS485​

  • The product has 4 isolated RS485 interfaces
  • The product supports all features in this tutorial: RS485 Usage Tutorial

Digital Input Interface​

warning

The maximum input voltage supported by the product's digital input interface is 36V.

Control PinFunctionDescription
GPIO24IN1Digital Input Channel 1
  • When the digital input is high (above 2V), the GPIO reads as low
  • When the digital input is low (below 0.9V), the GPIO reads as high

Relay​

Control PinFunctionDescription
GPIO25RelayNormally‑open (NO) and common (COM) terminals are brought out by default
  • When the GPIO outputs high, the relay is activated (NO and COM are connected)
  • When the GPIO outputs low, the relay is deactivated (NO and COM are disconnected)

4G/5G​

  • The product has an onboard M.2 M KEY interface, supporting 4G / 5G communication modules.
  • The product supports all features in this tutorial: 4G / 5G Usage Guide

Encryption Chip (ATSHA204)​

Buzzer​

Control PinFunctionDescription
GPIO22BuzzerActive buzze
  • When the GPIO outputs high, the buzzer is silent.
  • When the GPIO outputs low, the buzzer sounds.

LED Indicators​

LED LabelFunctionDescription
IN1Digital Input LEDWhen the input is high (above 2V), the LED is off
OUT1Relay status LEDWhen the relay is activated (NO and COM connected), the LED lights up
USER0User‑definable LED 0Connected to GPIO20, active low
USER1User‑definable LED 1Connected to GPIO26, active low
STA4G/5G module enable LED4G/5G module interface LEDs
NET4G/5G module status LED
PORT0RS485 CH0 communication LEDFlashes when RS485 communication is active
PORT1RS485 CH1 communication LED
PORT2RS485 CH2 communication LED
PORT3RS485 CH3 communication LED