RTD logo RTD Embedded Technologies, Inc.
An AS9100 and ISO 9001 Certified Company

PC/104-Plus Single Board Computer & Controller
1.0 GHz Intel® Celeron® M

CMA157 Single Board Computer
CMA157 Single Board Computer (side-view with heat sink installed)
Flat Heat Spreader Options Available
Rugged Fanless IDAN configuration
Product modifications available upon request.

Key Features

  • PC/104 Form Factor
  • PC/104-Plus Stackable Bus Structure
  • Complete PC-compatible Single Board Computer (SBC)
  • Intel Celeron M 1.0 GHz Processor on 90nm
  • Thermal throttling
  • Nonvolatile storage of CMOS settings without battery
  • Stackable 120-pin PCI bus
    • 4 Bus master add-on cards capable
  • 256 Mbytes Mbytes BGA DDR SDRAM (Surface-Mounted)
    • Up to 333 MHz Data Rate
  • 32-pin SSD socket:
    • Removable Onboard Miniature Industrial ATA/IDE Flash Drive up to 8GB (4GB Standard)
    • Flash Drive PIO Mode with BIOS-configured write protect function (available upon request)
    • Natively supported by all major operating systems
  • BIOS Selectable 14-bit Digital I/O with Advanced Digital Interrupt Modes with Ground and +5 VDC
  • 10/100 Ethernet with PXE Network Boot
  • Four RS-232/422/485 Ports
  • Four USB 2.0 (Universal Serial Bus) Ports
  • EIDE Controller with UltraDMA 100
  • 855GME SVGA controller Onboard with 3D Acceleration
  • DirectX & OpenGL 3D Accelerator
  • Advanced power management features
  • Advanced Thermal Management
    • Thermal Throttling reduces clock speed to prevent thermal runaway
    • Auto Fan Control only runs fan when needed
    • Hardware monitor for CPU temperature, board temperature, and power supply voltages
    • Mini Fan Heatsink with Auto Fan control
    • Passive Structural Heatsink & Heatpipes in IDAN and HiDAN System Configurations
  • Advanced Programmable Interrupt Controller (APIC)
  • 24 interrupt channels with APIC enabled (15 in legacy PIC mode)
  • 3 timer/counter channels
  • High resolution 100 MHz APIC timer
  • RTD Enhanced BIOS with ACPI, USB Boot and Quick Boot modes
  • Advanced Configuration and Power Interface (ACPI)
    • ACPI 1.0 Compliant
    • Supported power down modes: S1 (Power On Suspend), S3 (Suspend to RAM), S4 (Hibernate), and S5 (Soft-Off)
    • CPU Clock Throttling and Clock Stop for C0 to C3 Support
    • Also supports APM 1.2 for legacy power management
  • 3.3V or 5V PCI bus signaling
  • 400 MHz, source-Synchronous Front Side Bus
  • Supports MMX and SSE2 instructions
  • Math coprocessor
  • Internal Cache
    • L1 - 32KB of instruction and 32KB data; L2 - 2MB
  • Y2K compliant real time clock (external battery required)
  • Watchdog timer
  • PS/2 Mouse Port
  • Keyboard Port
  • Speaker Port

Technical Details

  • Fast Ethernet
    • Ethernet Controller
      • Intel 82562 Fast Ethernet PCI Controller
      • Integrated 3KByte Transmit and 3Kbyte Receive FIFOs
    • Physical Layer
      • 100Base-Tx and 10Base-T
      • Full Duplex support
    • Easy to Use
      • Low Power Features
      • LED Status
      • Software configuration
  • 855GME SVGA controller for CRT and LVDS Flat Panel
    • Analog SVGA Output
    • LVDS Flat Panel output
    • Resolution up to 2048 x 1536 pixels with 32K colors
    • Up to 16 million colors
    • 64-bit AGP Hardware graphics-accelerator
      • 2MB to 64MB of shared SDRAM high-performance memory
  • Four BIOS configurable RS-232/422/485 serial ports on two connectors, each connect configurable as:
    • One full RS-232 port with TxD, RxD, CTS, RTS, DSR, DTR, RI, and CD
    • One RS-422/485 port with TxD+, TxD-, RxD+, RxD-, with 120 ohm termination jumper
    • Two RS-232 ports:
      • One with TxD, RxD, CTS, and RTS
      • One with TxD and RxD
    • One RS-232 port with TxD and RxD, and one RS-422/485 port with TxD+, TxD-, RxD+, RxD-, with 120 ohm termination jumper
    • Jumper enabled two RS-422/485 ports each with TxD+, TxD-, RxD+, RxD-, with 120 ohm termination jumper
    • 16550 compatible UARTs for high-speed
  • 14 Advanced Digital I/O (aDIO)
    • One 8-bit-programmable I/O with Advanced Digital Interrupt Modes
      • Event Mode Interrupt generates an interrupt when any input bit changes
      • Match Mode Interrupt generates an interrupt when input bits match a preset value
      • External Strobe Mode latches 8 data inputs and generates and interrupt
    • One 4-bit port programmable as input or output
    • Two Strobes can be configured as readable inputs.
  • Four USB 2.0 (Universal Serial Bus) Ports
    • High-speed, full-speed, or low-speed
    • 500 mA @ 5 Vdc provided per port
    • USB Boot capability
  • UltraDMA-100 / 66 / 33 Master Mode PCI EIDE Controller
    • Transfer rate up to 100MB/sec using UltraDMA
    • Increased reliability using UltraDMA-33 transfer protocols
    • Support ATAPI compliant devices including DVD drives
    • 48-bit LBA support for hard drives larger than 137GB
  • Utility port
    • XK-CM77 Cable Kit Included
    • PC-AT compatible keyboard port
    • PS/2 Mouse Port
    • Speaker (0.1W output) port
    • Hardware Reset input
    • Battery input for Real Time Clock
  • Power I/O
    • Access to PC/104 Bus power pins
      • Gnd, ±12 & 5 VDC
    • Access to PC/104-Plus Bus pins
      • Gnd, ±12, 5 & 3.3 VDC
  • ISA Expansion Bus
    • Full ISA bus operation.
    • Supports 8-bit (XT) and 16-bit (AT) peripherals.
    • All ISA IRQ lines and DMA channels supported.
    • Supports both I/O-mapped and Memory-mapped expansion cards.
    • Subtractive Decode of PCI cycles
      • Existing software can be used without modification.
      • No special setup required.
  • Mating Connectors
    • Standard 12-pin 0.1" DIL header (Power)
    • Standard 10-pin 0.1" DIL header (Utility, COM1, COM2, USBs, Ethernet)
    • Standard 10-pin 2mm DIL header (SVGA)
    • Standard 20-pin 2mm DIL header (Panel)
    • Standard 16-pin 0.1" DIL header (aDIO)
    • Standard 44-pin 2mm DIL header (EIDE)


  • RTD Enhanced BIOS
    • Supports boot from IDE, USB, or Ethernet (PXE)
    • Serial Console Redirection
    • Flash-based CMOS Setup – No battery required to store settings
    • Fail Safe Boot – Load DOS even if no boot device is present
    • Special RTD Reliability Enhancements
  • Compatible with all x86 PC operating systems:
    • Windows (XP, XP Embedded)
    • Linux (desktop and real-time versions)
    • RTOSes such as QNX, VxWorks, Windows CE, and xPC Target
    • Note: Some hardware interfaces may require special drivers
  • Includes pre-installed Datalight ROM-DOS
  • Drivers and support provided for DOS, Windows, and Linux

Physical Attributes

  • Dimensions
    • Board Size
      • Length (L): 3.775 inches (95.89 mm)
      • Width (W): 3.550 inches (90.17 mm)
      • Stand-off Height: 0.600 inches (15.24 mm)
    • I/O Extension
      • Length (EL): 3.125 inches (79.375 mm)
      • Width (EW): 0.500 inches (12.700 mm)
  • Weight: Approximately 0.40 lbs. (0.19 Kg) with heat sink
  • Standard Operating Temperature: -40 to +85°C, 90% humidity non-condensing
  • Storage Temperature: -40 to +85°C
  • Power Consumption: 11.9 W @ 5 V Typical

Recommended Accessories

Documentation and Downloads

Ordering Information

Part Number Description Value
CMA157886CX1000HR-256   1.0 GHz PC/104-Plus cpuModule with 256MB DDR SDRAM & 4GB Flash Drive


—  Sequentially laminated PCB fabricated in accordance with IPC-6012 Class 3 Standards  —
*OEM price includes soldered 256MB SDRAM and 4GB Removable Flash Disk (8GB Flash Disk option available)


RTD Embedded Technologies, Inc.
Designed and Made in the USA
[email protected]   |   +1-814-234-8087