CM-X255 Computer-On-Module




The CM-X255 module is a tiny “system-on-module” computer, designed to serve as a building block in embedded applications. CM-X255 is advanced and backward-compatible version of original ARMCORE module, containing several significant improvements. The CM-X255 module has all the components needed to run operating systems such as Linux and Windows CE. Ready packages for these operating systems are available from CompuLab.

The CM-X255 is both small and inexpensive. Its small size allows integration into hand-held and mobile applications, providing a powerful computing core. Its exceedingly low price makes it an ideal selection for cost-sensitive applications. Based on Intel’s XScale architecture, the CM-X255 delivers a price/performance ratio significantly better than available from x86-based counterparts.

The feature set of the CM-X255 module combines a 32-bit CPU, SDRAM, Flash Disk and vital computing peripherals. For embedded applications, the CM-X255 provides a 32-bit PCI bus, 100Mbit Ethernet, serial ports, general purpose I/O lines and many other essential functions.

Standardized CAMI (“CompuLab’s Aggregated Module Interface”) connectors of CM-X255 module allow interchangeability with other CORE modules, enabling the flexibility required in a dynamic market where application requirements can change rapidly.

Software support for the CM-X255 includes ready-to-run packages for:

* Linux
* Windows CE

See O/S Support Coverage Map




  • Full-featured Single Board Computer on module
  • Basic configuration price below $50 !
  • Intel’s XScale PXA255 CPU, up to 400 MHz, 32+32 KB cache
  • General purpose bus and optional PCI, LPC, AC97 busses
  • 16 – 64 Mbyte SDRAM
  • 1 – 512 Mbyte Flash Disk
  • Graphics Controller for STN and TFT panels
    see LCD panel support
  • PCMCIA controller
  • Sound codec with speaker and microphone support (optional)
  • Touchscreen Controller (optional)
  • Slave and host USB ports (optional)
  • Standard peripherals: serial ports, LPT port, I/O ports, FDC, PS/2 keyboard and mouse, IrDA, HDD interface (optional)
  • 10/100BaseT Ethernet port (optional)
  • Power consumption below 1W
  • 66 x 44 mm size
  • Interchangeable with other CORE modules via CAMI connectors
  • SBC-X255 – turns the CM-X255 module into a PC/104+ single board computer


Block diagrams



“Option” column specifies the configuration code required to have the particular feature. “+” means that the feature is available always.

CPU & Core logic, Memory and Busses

CPUIntel XScale PXA255, 100 - 400 MHz +
Address Space128 MB+
Internal Bus32-bit, 100 MHz+
Cache32 KB I-cache and 32 KB D-cache, WB+
Core LogicDMA and Interrupt controllers, Timers+
RTCReal Time Clock, powered by external lithium batteryR
DRAM16 - 64 MB, SDRAM, 100 MHz, 32-bit+
NOR Flash Disk1 - 4 Mbytes+
NAND Flash Disk16 - 512 Mbytes, optionalN
I/O ToleranceLocal Bus - 3.3V, PCI - 5V+
External BussesLocal bus / PCMCIA, PCI, LPC, AC97
External local bus16-bit, variable rate up to 100 MHz+
AC97AC97 / AMC97 Rev 2.1 compliant+
PCI bus32-bit, 2.1-compliant, 132 MB/s, arbiter for 4 mastersB
LPC busHost, 33 MHz, Intel LPC v1.0 compatibleB
JTAG InterfaceAvailable+


Graphics Controller4/8/16 bit color, TFT / STN, resolution up to 1024 x 768, frame buffer in system SDRAM.+
USBOne Slave port, 12 Mbps
Two Host ports, 1.5 / 12 Mbps, OHCI v1.0 compliant
Serial Ports
Up to 5 UART ports, 16550 compatible, max 230 - 960 kbps
COM-A - RS232 Rx/Tx, partial modem
COM-B - TTL, Rx/Tx
COM-C - TTL, full modem
COM-D - TTL, full modem
COM-E - TTL, Rx/Tx, shared with FIR
COM-F - TTL, partial modem. (shared with other essential funct.

General Purpose I/O5 dedicated lines plus about 40 lines shared with other functions. Can be also used as interrupt inputs.+
Hard Disk InterfaceIDE, PIO mode+
LPT - Parallel Port Bi-directional with EPP mode.B,S
Floppy Disk InterfaceRouted through LPT pinsB,S
Keyboard InterfacePS/2 or redirection from COMB,S
Mouse InterfacePS/2B,S
Infrared (IrDA) PortUp to 115Kbps in SIR mode, 4Mbps in FIR mode+
EthernetMAC & PHY, 10/100BaseT, Activity LED's. The ethernet port is implemented differently than in the previous version:
Version 2 - Realtek 8139, on PCI bus. Requires Interface Bridge
Version 3 - Davicom DM9000, on local bus

Audio codecCrystal CS4299 or Phillips UCB1400, AC97 interface, mono microphone input, stereo line input and 25 mW output for active speakersA
Touchscreen ctrl.A part of the UCB1400 codec chip. Supports resistive touch panels. (This feature is not available in the previous version 2 of CM-X255)AT
PCMCIA controllerDirect support for 1st slot, hooks for 2nd slot, 8/16 bit interface+

Electrical, Mechanical and Environmental Specifications

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Development resources