CM5-HMI-BOX-A

The CM5-HMI-BOX-A is an industrial computer designed for use with the Raspberry Pi Compute Module 5. It features an aluminum alloy heat-dissipating enclosure, an onboard supercapacitor module with power-loss protection. The product provides M.2 NVMe and 4G / 5G expansion capabilities, and integrates industrial interfaces such as RS485, CAN, digital input/output, and analog input, making it suitable for industrial communication and data acquisition. The product does not include the CM5 core board.

SKU	Model	Version Difference
35745	CM5-HMI-BOX-A (US)	4 × RS485
35746	CM5-HMI-BOX-A (EU)	4 × RS485
35747	CM5-HMI-BOX-A (UK)	4 × RS485
35748	CM5-HMI-BOX-B (US)	2 × RS485, 2 × RS232
35749	CM5-HMI-BOX-B (EU)	2 × RS485, 2 × RS232
35750	CM5-HMI-BOX-B (UK)	2 × RS485, 2 × RS232

Version Options

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 M.2 M KEY interface, supports NVMe SSD (or PCIe‑based AI modules)
• Onboard M.2 B KEY interface, supports 4G/5G communication modules
• Optional versions: 2x RS485 + 2x RS232, or 4x RS485 (isolated)
• 1x CAN supporting 1Mbps communication rate (isolated)
• 2x Digital Output + 2x Digital Input (isolated)
• 2x ADC analog input (4 - 20mA current acquisition can be achieved by desoldering components)
• Single controllable buzzer
• Onboard EEPROM and encryption chip
• 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 flashing, do not connect other devices; otherwise, insufficient power may cause the device not to be recognized
• Onboard supercapacitor module, supporting power-loss protection
• Multiple onboard power supply options (green terminal 7-36V power supply, Type-C 5V power supply)

Onboard Resources

1. CM5 connector
   Compatible with all versions of the Compute Module 5
2. TF card slot
   For connecting a TF card with an OS; only applicable to CM5 versions without eMMC
3. Type-C port
   Can be used as a 5 V, 5 A power supply interface, eMMC flashing interface, or USB OTG interface
4. FAN connector
   5 V, 4PIN JST-SH PWM fan connector, connected in parallel with connector 8; only one fan may be connected
5. Serial communication indicators
6. Dual MIPI interfaces
   Supports connecting a DSI display or CSI camera
7. RTC battery header
   For connecting an RTC battery
8. FAN connector
   5 V, 4PIN JST-SH PWM fan connector, connected in parallel with connector 4; only one fan may be connected
9. 5V output header
   Provides 5 V output
10. PSW power button
    Long press to force power off, short press to soft power off or on
11. BOOT button
    Press before powering on, release after powering on to enter flashing mode
12. System function indicators
13. M.2 M KEY
    Supports 2280, 2260, 2242, and 2230 form-factor NVMe SSDs or PCIe AI modules
14. M.2 B KEY
    Supports 4G / 5G communication modules

15. RS485 terminal resistor jumper
    When the corresponding interface is RS232, the terminal resistor at this position is ineffective
16. RS485 / RS232 interface
    The interface type depends on the product version
17. CAN terminal resistor jumper
    Used to configure the CAN bus terminal resistor
18. Multi-function interfaces
    1 × CAN interface with up to 1Mbps, 2 × digital inputs, 2 × digital outputs, and 2 × analog inputs
19. DC power screw terminal
    Supports 7-36 V DC power supply
20. Buzzer
21. Power-Loss protection capacitors
22. Charging enable jumper
    Set the jumper to ON to charge the supercapacitor. Charging automatically stops when the capacitor is fully charged
23. HDMI port
    Supports 4K output
24. Dual USB 3.0 ports
    2 × USB 3.2 Gen1 Type-A port with up to 5Gbps rate
25. Dual USB 2.0 ports
    2 × standard USB 2.0 Type-A ports
26. 1000M Ethernet port
    RJ45 1000M Ethernet port, supporting 10M / 100M / 1000M network access
27. Nano SIM card slot

Dimensions

Development Resources

Image Flashing

• Entering download mode
  • Onboard BOOT Button: Press and hold the BOOT button before powering on, connect to PC via Type-C, and release the button after the power indicator lights up
• Flashing Images for LITE Versions: LITE Version Tutorial
• Flashing Images for EMMC Versions: EMMC Version Tutorial

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NVMe(M.2 M KEY)

• The product supports all features in this tutorial: NVMe Usage Tutorial
• Includes: Formatting the Hard Drive | Hard Drive Partitioning | Manual Mounting | Auto-mount on Boot | Read/Write Test

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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

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MIPI

• You can add specific content to config.txt to select using DSI or CSI connection
• MIPI - DSI
  • The product supports all features in this tutorial: DSI Interface Usage Tutorial
  • DSI includes: DSI Interface Selection
• MIPI - CSI
  • The product supports all features in this tutorial: CSI Interface Usage Tutorial
  • CSI includes: CSI Interface Selection (Driver Settings) | Camera Detection | Displaying Real-time Preview | Taking a Photo | Recording a Video

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Fan Control

warning

The product does not include a fan; only a fan connector is provided on the carrier board.

• The product supports all features in this tutorial: Fan Usage Tutorial
• Includes: Manual Speed Control | View Current Speed | Restore Automatic Temperature Control

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RTC

• With an RTC battery connected, the product supports all features in this tutorial: RTC Usage Tutorial
• Includes: Get RTC Time | Set RTC Time | Synchronize RTC Clock | Scheduled Shutdown | Scheduled Power-on - Low Power Wake-up | RTC Battery Charging

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RS485/RS232

• The product features onboard RS485/RS232 interfaces (Version A does not have RS232)
• The product supports all features in this tutorial: RS485/RS232 Usage Tutorial

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CAN

• The product has an onboard CAN interface (supports up to 1Mbps).
• The product supports all features in this tutorial: CAN Usage Guide

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Analog Input Interface

warning

The product's analog input interface is implemented via the SGM58031XMS10G, expanded through I2C1.

• The I2C address of the analog acquisition chip (SGM58031XMS10G) on this product: 0x48
• The default I2C connection for the chip is: I2C1 (SDA:GPIO2, SCL:GPIO3) I2C1 (SDA:GPIO2, SCL:GPIO3)

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Digital Input Interface

warning

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

Control Pin	Function	Description
GPIO23	IN1	Digital Input Channel 1
GPIO24	IN2	Digital Input Channel 2

• 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

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Digital Output Interface

warning

The product's digital output is open-drain, with a maximum cut-off voltage of 150V and a maximum current of 500mA (on-resistance is 18Ω). Overvoltage or overcurrent will damage the device.

Control Pin	Function	Description
GPIO27	OUT1	Digital Output Channel 1
GPIO22	OUT2	Digital Output Channel 2

• When the GPIO outputs high, the digital output level is low
• When the GPIO outputs low, the digital output level is high-impedance

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4G/5G

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

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Encryption Chip (ATSHA204)

• I2C address of this product's encryption chip (ATSHA204): 0x64
• The default I2C used by this product's encryption chip (ATSHA204) is: I2C1 (SDA:GPIO2, SCL:GPIO3)
• The product supports all features in this tutorial: ATSHA204 Usage Tutorial
• Includes: Data Read/Write | Chip Configuration Area Description

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EEPROM (CAT24C32)

• I2C address of the chip: 0x50 (adjustable by changing the soldering position of resistors A0~A2)
• The default I2C connection for the chip is: I2C1 (SDA:GPIO2, SCL:GPIO3) I2C1 (SDA:GPIO2, SCL:GPIO3)

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Power-Loss Protection

warning

• The product's power-loss protection only takes effect when using 7-36V power supply, with capacitor charging enabled and the capacitor fully charged.
  
• After the power-loss protection function is enabled, the supercapacitor will provide additional power to the device for a period of time when the external power is lost, giving the user time to back up data.

• After the capacitor power-loss protection function is enabled, the supercapacitor will provide additional power to the device for a period of time when the external power is lost, giving the user time to back up data.
• The product enables capacitor power-loss protection by default. To disable this function, move the jumper cap next to the large capacitor in the upper-left corner to OFF.

Control Pin	Function	Description
GPIO11	Capacitor Low-Voltage Warning	When the capacitor voltage is too low, the warning circuit pulls GPIO11 low
GPIO16	External Power Cut Warning	When both the external Type-C and 7V-36V terminals are unpowered and the supercapacitor is providing backup power, the power-cut warning circuit pulls GPIO16 high

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Buzzer

Control Pin	Function	Description
GPIO7	Buzzer	Active buzzer

• When the GPIO outputs high, the buzzer is silent.
• When the GPIO outputs low, the buzzer sounds.

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LED Indicators

LED Label	Function	Description
STAT	4G/5G module enable LED	4G/5G module interface LEDs
NET	4G/5G module status LED
PWR	Raspberry Pi system LEDs	Raspberry Pi system LEDs
ACT	Raspberry Pi activity LED
USER1	User‑definable LED 1	Connected to GPIO25, active low
USER2	User‑definable LED 2	Connected to GPIO26, active low