INTRODUCTION
GENERAL
The 4C27 is a high integration, low power, all CMOS, AT compatible CPU implemented on the
PC/104 bus. With the built-in ethernet interface, the 4C27 is ideally suited to network accessible
systems suchasembeddedweb servers or network accessible monitoringsystems. The 4C27has a40
MHz 386SX-compatible CPU/chipset. System RAM can be 2, 4, or 8M bytes depending on model.
Flash disk canalso be4, 8, or 16M bytes. Theflash disk issupported bythe 4C27's BIOS, and appears
to the system as a standard disk drive. High performance NAND flash devices are used, giving fast
writespeeds, andverylonglife.
A precision reset circuit, watchdog timer, EEPROM setup storage, Ethernet interface, and built
indiskemulator make the4C27especiallysuitedto embeddedapplications.
The4C27BIOSEPROM canuse flashmemoryto allowfield upgrades without physicalaccessto
the 4C27 card. The BIOS can be configured to skip various device probes at startup, allowing a fast
boot-upinembeddedapplications..DatalightROM-DOSisavailableasa4C27option.
On card 4C27 I/O includes two 16C550 type RS-232 serialports, a bi-directionalparallelport, a
floppyinterface, anIDE interface, and ahighperformance CS8900based10BaseTethernetinterface.
The second serial port can optionally be configured for an RS-485 interface. All standard AT
logic is provided by the 4C27, including NPU interface, 2 interrupt controllers, 2 DMA controllers,
keyboardcontroller,andbatterybackedclock.
Configuration storage is provided byan EEPROM, which is much more resistant to inadvertent
corruptionthanthebatterybackedCMOSconfigurationstorageinastandardAT.
4C27 power consumption is 3W maximum with CPU running and down to .5 W with CPU
stopped. The RS-232 interface power is generated on card, so only +5V power is required by the
4C27.
4C27 CPU USER'S MANUAL
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