INTRODUCTION
GENERAL
The 4C24 is a low power, all CMOS, AT compatible CPU implemented on the PC/104 bus. The
4C24canusevariousCPU'sfrom33MHz386SXtoa 25/50MHzTI486SLC2CPU.ACyrix87SLC
math coprocessor is available as an option. System memorycanbe 1M byte or 4M bytes. A precision
reset circuit, watchdog timer, EEPROM setup storage, and built in disk emulator make the 4C24
especiallysuitedtoembeddedapplications.
Two disk emulator sockets are provided. These sockets can use 5V flash EEPROM or EPROM.
Total disk emulator capacity is 1 M byte using flash EEPROM, or 2 M bytes using EPROM. The
emulated drive is bootable and has full compatibility with application and operating system software.
Writing to the flash disk is just a standard DOS write, no special programs are needed for writing or
packing the flash disk. Allutilities for using the disk emulator are providedwiththe4C24.
The 4C24BIOS EPROM canuseflashmemoryto allowfieldupgrades without physicalaccess to
the 4C24 card. The 4C24 BIOS is normally 64K bytes but can be extended to 128K bytes to
accommodate Datalight ROM DOS or other built in operatingsystems.
On card 4C24 I/O includes two RS-232 serial ports, a bi-directional parallel port, and an AT
compatible keyboard port. The serial interface chips used on the 4C24 are compatible with 16C550A
UARTs, with16characterreceiveandtransmitFIFOs.
All standard AT logic is provided by the 4C24, including 2 interrupt controllers, 2 DMA
controllers, keyboard controller, and battery backed clock. Configuration storage is provided byan
EEPROM,whichismuchmoreresistant to inadvertent damagethat theCMOS configurationstorage
in a standard AT. The BIOS autodetects IDE hard drive parameters and floppy drive types, so that
setupinformationneednotbechangedwhenchangingdrives.
4C24 power consumption is 4W maximum with the 486SLC CPU and 3W maximum with the
386SX. CPU clock and numeric coprocessor clock can be slowed to conserve power when the full
CPU speedisnot required. The RS-232 interfacepoweris generated oncard, sothat only+5V power
isrequiredbythe4C24
4C24 CPU USER'S MANUAL
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