MESA Electronic 4C24, Руководство пользователя

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CONFIGURATION
WATCHDOG ENABLE
The 4C24 has a hardware watchdog timer that will reset the CPU unless 'fed' periodically by
system software. In a DOS environment, the BIOS performs this service when it services the
hardware tic interrupt. When other operating systems are used, (Linux,PSOS,QNX etc) it may be
necessary to disable the watchdog. Watchdog enable is controlled by jumper W1. When W1 is in the
up position, the watchdog is enabled. When W1 is in the down position, the watchdog is disabled.
DISK EMULATOR TYPE SELECTION
The 4C24 has two 32 pin PLCC sockets available disk emulator use. These sockets are the two
upper sockets on the 4C24 (U11 and U14). The disk emulator can use EPROM or 5V flash
EEPROM. Each socket can be configured independently. This allows the creation of dual drive (C:
and D:) disk emulator systems using different memory technologies. For example. A system could be
configured with a 512K EPROM disk for program storage, and a 128K flash EEPROM disk for data
collection. If both sockets use the same chip type, they can be combined into a single, larger disk
emulator.
The 4C24 disk emulator hardware needs to be configured to match the memory type used. W2
selects the memory type for socket U14 (disk 1). The jumper needs to be set to the up position for flash
EEPROM and the down position for EPROM > 512K.
For more information on disk emulator usage, see the CPU operation section of the manual.
You must use a PLCC chip extraction tool when removing disk chips from the 4C24.
Improvised tools such as bent paper clips etc. can damage the PLCC socket, the chip and/or the
4C24 circuit card. Such damage will void the 4C24 warranty.
LITHIUM CELL ENABLE
The 4C24 has Lithium coin cell that powers the clock/calendar and the CMOS setup storage
RAM. If jumper W8 is removed or placed on one pin, the Lithium cell will be disconnected. The 4C24
is shipped with the cell disconnected, so you must install W8 on both pins in order to use the battery
backed clock/calendar.
The 4C24 BIOS does not use the CMOS setup RAM, so it is possible to run the 4C24 with no
Lithium cell if desired.
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4C24 CPU USER'S MANUAL