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 such as embedded web servers or network accessible monitoring systems. The 4C27 has a 40
MHz 386SX-compatible CPU/chipset. System RAM can be 2, 4, or 8M bytes depending on model.
Flash disk can also be 4, 8, or 16M bytes. The flash disk is supported by the 4C27's BIOS, and appears
to the system as a standard disk drive. High performance NAND flash devices are used, giving fast
write speeds, and very long life.
A precision reset circuit, watchdog timer, EEPROM setup storage, Ethernet interface, and built
in disk emulator make the 4C27 especially suited to embedded applications.
The 4C27 BIOS EPROM can use flash memory to allow field upgrades without physical access to
the 4C27 card. The BIOS can be configured to skip various device probes at startup, allowing a fast
boot-up in embedded applications.. Datalight ROM-DOS is available as a 4C27 option.
On card 4C27 I/O includes two 16C550 type RS-232 serial ports, a bi-directional parallel port, a
floppy interface, an IDE interface, and a high performance CS8900 based 10BaseT ethernet interface.
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,
keyboard controller, and battery backed clock.
Configuration storage is provided by an EEPROM, which is much more resistant to inadvertent
corruption than the battery backed CMOS configuration storage in a standard AT.
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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