MTH253 Embedded 4" SBC User's Manual

© June 27, 2025 DFI Inc.

This manual provides comprehensive information for the DFI MTH253 Embedded 4" Single Board Computer (SBC). It covers specifications, hardware installation procedures, and detailed BIOS settings.

DFI Inc. is the manufacturer of this product.

About this Manual

This manual can be retrieved from the DFI website. The manual is subject to change and update without notice and may be based on editions that do not resemble your actual products. Please visit the DFI website or contact DFI sales representatives for the latest editions.

Warranty

1. Warranty does not cover damages or failures arising from misuse of the product, inability to use the product, unauthorized replacement or alteration of components and product specifications.
2. The warranty is void if the product has been subjected to physical abuse, improper installation, modification, accidents, or unauthorized repair of the product.
3. Unless otherwise instructed in this user's manual, the user may not, under any circumstances, attempt to perform service, adjustments, or repairs on the product, whether in or out of warranty. It must be returned to the purchase point, factory, or authorized service agency for all such work.
4. DFI Inc. will not be liable for any indirect, special, incidental, or consequential damages to the product that has been modified or altered.

About this Package

The package typically contains the following items. If any of these items are missing or damaged, please contact your dealer or sales representative for assistance:

• 1 MTH253 board
• 1 Heatsink for 15W CPU or 1 Cooler for 28W CPU
• Heat spreader

Note: The items are subject to change in the developing stage. The product and accessories in the package may not come exactly as the information listed above. This may differ in accordance with the sales region or models in which it was sold. For more information about the standard package in your region, please contact your dealer or sales representative.

Static Electricity Precautions

It is crucial to take extra care when handling the system board and its components to prevent damage from electrostatic discharge (ESD). ESD can damage computer components without causing visible signs of physical damage.

1. To prevent electrostatic build-up, leave the system board in its anti-static bag until you are ready to install it.
2. Wear an antistatic wrist strap.
3. Perform all preparation work on a static-free surface.
4. Hold the device only by its edges. Be careful not to touch any of the components, contacts, or connections.
5. Avoid touching the pins or contacts on all modules and connectors. Hold modules or connectors by their ends.

Important: Electrostatic discharge (ESD) can damage your processor, disk drive, and other components. Perform upgrade instruction procedures described at an ESD workstation only. If such a station is not available, you can provide some ESD protection by wearing an antistatic wrist strap and attaching it to a metal part of the system chassis. If a wrist strap is unavailable, establish and maintain contact with the system chassis throughout any procedures requiring ESD protection.

Safety Precautions

• Use the correct DC / AC input voltage range.
• Unplug the power cord before removing the system chassis cover for installation or servicing. After installation or servicing, cover the system chassis before plugging in the power cord.
• There is a danger of explosion if the battery is incorrectly replaced.
• Replace only with the same or equivalent specifications of batteries recommended by the manufacturer.
• Dispose of used batteries according to local ordinances.
• Keep this system away from humid environments.
• Make sure the system is placed or mounted correctly and stably to prevent the chance of dropping or falling which may cause damage.
• The openings on the system shall not be blocked and shall be kept at a distance from other objects to ensure proper air ventilation and protect the system from overheating.
• Dress the cables, especially the power cord, so they will not be stepped on, come into contact with high-temperature surfaces, or cause any tripping hazards.
• Do not place anything on top of the power cord. Use a power cord that has been approved for use with the system and is compliant with the voltage and current ranges required by the system's electrical specifications.
• If the system is to be unused or stored for a long time, disconnect it from the power source to avoid damage by transient overvoltage.
• If one of the following occurs, consult a service personnel:
  • The power cord or plug is damaged.
  • Liquid has penetrated the system.
  • The system has been exposed to moisture.
  • The system is not working properly.
  • The system is physically damaged.
• The unit uses a three-wire ground cable equipped with a third pin to ground the unit and prevent electric shock. Do not defeat the purpose of this pin. If your outlet does not support this kind of plug, contact an electrician to replace the outlet.
• Disconnect the system from the electricity outlet before cleaning. Use a damp cloth for cleaning the surface. Do not use liquid or spray detergents for cleaning.
• Before connecting, make sure that the power supply voltage is correct. The device is connected to a power outlet which should have a grounded connection.

The system may burn fingers while running. Wait for 30 minutes to handle electronic parts after power off.

Chapter 1 - Introduction

Specifications

Note: For more information about OOB setup, please visit DFI website at : https://pages.dfi.com/oob-solutions#M2A-OOB

Dimensions

Refer to the diagrams for detailed dimension information.

Block Diagram

The block diagram illustrates the system architecture and component interconnections.

Chapter 2 - Hardware Installations

Overview

Top View

Diagram showing the top view of the MTH253 board with numbered components.

Bottom View

Diagram showing the bottom view of the MTH253 board with numbered components.

Jumper Settings

COM4 Port / DIO Selection (TSJP1 & TSJP2)

Diagram illustrating jumper settings for COM4 Port / DIO Selection.

• 2-3/5-6/8-9/11-12 short: DIO
• 1-2/4-5/7-8/10-11 short: COM4 (Default)

Panel Backlight ON Level Selection (DPJP1)

Diagram illustrating jumper settings for Panel Backlight ON Level Selection.

• 1-2 short: 3V3 (Default)
• 2-3 short: 5V

Inverter Panel Power Selection (DPJP2)

Diagram illustrating jumper settings for Inverter Panel Power Selection.

• 1-2 short: 12V (Default)
• 2-3 short: 5V

VCC Panel Power Selection (DPJP3)

Diagram illustrating jumper settings for VCC Panel Power Selection.

• 1-2 short: 12V
• 3-4 short: 5V
• 5-6 short: 3V3 (Default)

Pin Assignment

RTC Battery (CN7)

Case Open (CN11)

System Fan (CN12)

SATA Power (CN1)

I2C (CN6)

SATA0 (J1)

Front Panel (J2)

COM5 (TSCN5)

COM6 (TSCN6)

USB2.0 (UBCN4)

eSPI (CN8)

LVDS (DPCN1)

eDP SKU (DPCN1) - Optional

Expansion Slots

Installing the M.2 Module

Before installing the M.2 module into the M.2 socket, please ensure the following safety precautions are followed:

1. Make sure the PC and all other peripheral devices connected to it have been powered down.
2. Disconnect all power cords and cables.
3. Locate the M.2 socket on the system board.
4. Ensure the notch on the card is aligned with the key on the socket.
5. Ensure the standoff screw is removed from the standoff.

Installation Steps:

1. Step 1: Insert the card into the socket at an angle, ensuring the notch and key are perfectly aligned.
2. Step 2: Press the end of the card far from the socket down until it rests against the standoff.
3. Step 3: Screw the card tightly onto the standoff with a screwdriver and a standoff screw until the gap between the card and the standoff closes. The card should be lying parallel to the board when correctly mounted.

Chapter 3 - BIOS Settings

Overview

The BIOS (Basic Input/Output System) is a program that manages the fundamental communication between the CPU and peripherals. It contains codes for advanced system features and allows for system configuration, with settings stored in battery-backed CMOS memory. If the CMOS battery fails, BIOS settings may be lost and require reconfiguration.

Note: BIOS screens may vary due to updates. The screens in this chapter are for reference only.

Default Configuration

Most configuration settings are predefined or automatically detected. Some settings may require manual adjustment based on your system configuration.

Entering the BIOS Setup Utility

The BIOS Setup Utility is operated via the keyboard. After powering up the system, a BIOS message appears, followed by memory count. The prompt "Press DEL to run setup" will appear. If missed, restart the system or press the Reset button. Alternatively, press <Ctrl> + <Alt> + <Del> simultaneously.

Legends

Scroll Bar

A scroll bar indicates additional fields not visible on the current screen. Use the arrow keys to navigate.

Submenu

A "$" symbol indicates a submenu with additional options. Press <Enter> to access.

Main

The Main menu is the first screen displayed upon entering the BIOS Setup Utility.

System Date

Format: <month>, <date>, <year>. Use "Tab" to switch fields and "." or "+" to modify values.

System Time

Format: <hour>, <minute>, <second> (24-hour format). Hours: 00-23, Minutes: 00-59, Seconds: 00-59.

Advanced

The Advanced menu allows configuration for basic system operation and performance enhancement.

Important: Incorrect field values may cause system malfunction.

CPU Configuration Parameters

Details on CPU configuration settings.

CPU Configuration

Intel (VMX) Virtualization Technology: When enabled, the VMM can utilize the additional hardware capabilities provided by Vanderpool Technology.

Hyper-threading: Enables this feature for Windows XP and Linux optimized for Hyper-Threading technology. Select disabled for other OSes not optimized for Hyper-Threading technology. When disabled, only one thread per enabled core is active.

AES: Enable or disable the AES function.

Note: Some fields may not be available if not supported by the equipped CPU.

Power & Performance

Configuration options for power and performance management.

CPU- Power Management Control

System Agent (SA) Configuration

Settings related to the System Agent.

Memory Configuration Parameters

Parameters for memory configuration.

Graphics Configuration

Settings for graphics configuration.

PCIE Configuration

Configuration options for PCI Express slots.

PCH-IO Configuration

SATA Configuration

Settings for SATA device options.

SATA Configuration

SATA Configuration

HD Audio Configuration

HD Audio Subsystem Configuration Settings

• HD Audio
• Disabled
• Unmixed

Control Detection of the HD Audio Device:

• Disabled: HDH will be unconditionally disabled.
• Enabled: HDH will be unconditionally enabled.

HDA Audio: Control the detection of the HD Audio device.

• Disabled: HDA will be unconditionally disabled.
• Enabled: HDA will be unconditionally enabled.

HDA State:

• Unmixed
• Fireware Update Configuration

Trusted Computing

IT8786 Super IO Configuration

Serial Port 3, 4 Configuration

Configuration settings for Serial Ports 3 and 4.

• Serial Port: [Enabled]
• Device Settings: IO=3E8h; IRQ=6;

Serial Port 5, 6 Configuration

Configuration settings for Serial Ports 5 and 6.

• Serial Port: [Enabled]
• Device Settings: IO=2F0h; IRQ=10;

• Serial Port: [Enabled]
• Device Settings: IO=2E0h; IRQ=7;

IT8786 Hardware Monitor

Displays system health information including voltage, CPU and system temperatures, and fan speeds.

Smart FAN Function

Smart Fan is a fan speed moderation strategy based on system temperature. Fan speed increases as system temperature rises above the set boundary.

CPU_FAN Setting

• Smart Fan Mode: [Automatic Mode]
• Fan off temperature limit: 0
• Fan start temperature limit: 60
• Fan full speed temperature limit: 90
• Fan start PWM: 75

Smart FAN Mode Select: Select the Smart Fan mode.

Fan off temperature limit: Fan turns off when temperature is below this limit.

Fan start temperature limit: Fan operates when temperature is above this limit.

Fan full speed temperature limit: Fan runs at full speed when temperature is above this limit.

Fan start PWM: Fan starts with this PWM value.

Serial Port Console Redirection

Enables Console Redirection for a COM port, making sub-menu settings available.

Console Redirection Settings

Configure serial settings for the current COM port.

• Terminal Type: [VT100Plus]
• Bits per second: [115200]
• Data Bits: [8]
• Parity: [None]
• Stop Bits: [1]

Emulation: ANSI: Extended ASCII char set. VT100: ASCII char set. VT100+: Extends VT100 to support color, function keys, etc. VT-UTF8: Uses UTF8 encoding to map Unicode chars onto 1 or more bytes.

ACPI Settings

Wake system from S5 via RTC: When Enabled, the system will automatically power up at a designated time daily. Configure the time of day (hour, minute, second) for the system to wake up.

State After G3: Select between S0 State, and S5 State. This field specifies the system state upon power restoration after a power failure (G3 state).

• S0 State: The system automatically powers on after power failure.
• S5 State: The system enters soft-off state after power failure. A power-on signal input is required to power up the system.
• Last State: The system returns to the last state before power failure.

Network Stack Configuration

Network Stack: Enable or disable UEFI network stack. Subsequent fields appear when enabled.

IPv4 PXE/HTTP Support: Enable or disable IPv4 PXE/HTTP boot support. If disabled, IPv4 PXE/HTTP boot support will not be available.

IPv6 PXE/HTTP Support: Enable or disable IPv6 PXE/HTTP boot support. If disabled, IPv6 PXE/HTTP boot support will not be available.

PXE boot wait time: Set the wait time in seconds to press ESC key to abort PXE boot. Use +/- or numeric keys.

Media detect count: Set the number of times media presence is checked. Use +/- or numeric keys.

DFI WDT Configuration

USB Power Control

Security

Administrator Password

Set the administrator password. To clear, input nothing and press enter when prompted for a new password. Administrator Password is required to enter the BIOS.

Secure Boot

The Secure Boot feature stores a database of certificates in the firmware, allowing only OSes with authorized signatures to boot. To activate Secure Boot:

• Ensure "Secure Boot" is set to "[Enabled]".
• Platform Key (PK) must be enrolled.
• "System Mode" must be "User".
• CSM must be disabled.

After enabling/disabling Secure Boot, save the configuration and restart the system. When configured correctly, the Secure Boot status will be "Active".

Secure Boot Mode

Select the secure boot mode: Standard or Custom. In Custom mode, users can manually modify key databases.

Restore Factory Keys

Forces the system to User Mode and loads OEM-defined factory defaults for keys and databases onto Secure Boot. Press Enter and confirm.

Reset To Setup Mode

Clears all keys and signatures from NVRAM. Press Enter and confirm.

Expert Key Management

Enables expert users to modify Secure Boot Policy variables without full authentication.

Boot

Setup Prompt Timeout

Set the number of seconds to wait for the setup activation key. 65535 (0xFFFF) means indefinite waiting.

Bootup NumLock State

Select the keyboard NumLock state: On or Off.

Quiet Boot

Enable or disable the quiet boot option.

Boot Option Priorities

Rearrange the system boot order of available boot devices.

Save & Exit

Save Changes and Reset

To save changes, select this option and press <Enter>. Confirm by selecting Yes in the dialog box to reset the system.

Discard Changes and Reset

To discard changes, select this option and press <Enter>. Confirm by selecting Yes to reset the system setup without saving.

Restore Defaults

To restore optimized default values, select this option and press <Enter>. Confirm by selecting Yes to restore all setup options to their default values.

Boot Override

Move the cursor to an available boot device and press Enter to immediately boot from the selected device for the current session only. This does not change the "Boot Option Priorities".

• Save Setting to file: Select this option to save BIOS configuration settings to a USB flash device.
• Restore Setting from file: This option appears when a USB flash device is detected. Select it to restore settings from the USB flash device.

Updating the BIOS

To update the BIOS, you will need the new BIOS file and a flash utility. Please contact technical support or your sales representative for the files and specific instructions on how to update the BIOS with the flash utility.

Notice: BIOS SPI ROM

1. The Intel ® Management Engine is integrated into this system board. Due to safety concerns, the BIOS (SPI ROM) chip cannot be removed and used on another system board of the same model.
2. The BIOS (SPI ROM) on this system board must be the original factory equipment and cannot be used to replace one utilized on other system boards.
3. Failure to follow these methods will result in the Intel ® Management Engine not being updated and ceasing to be effective.

Note:

• Flash tools can be used to update the default BIOS (SPI ROM) configuration to the latest version at any time.
• If the BIOS IC needs replacement, populate it properly onto the system board after the EEPROM programmer has been burned and follow technical person's instructions to confirm whether the MAC address should be burned or not.
• After updating the unique MAC Address from manufacturing, NVM will be protected immediately after a power cycle. Users cannot update NVM or MAC address.