Midas RTE-V821-PC, Руководство пользователя

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RTE-V821-PC USER’ S MANUAL
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[Caution]
When you have to cut an oscillator or crystal pin for convenience, be careful not to
cut it too short, or otherwise the frame (housing) of the oscillator crystal may touch a pin in the
socket, resulting in a short-circuit occurring.
[Note] When the clock frequency is changed, it is necessary to review the refresh interval of
the DRAM. The system clock is factory-set to a range of 12 to 25 MHz by the ROM initialization
routine.
3.11. DRAM-SIMM SOCKETS
The RTE-V821-PC has DRAM-SIMM socket used to install 4 Mbytes (standard) of SIMM.
Each socket can hold a 72-pin 4-, 8-, or 16-Mbyte SIMM (known as a module for DOS/V
machines), so it is easy to expand the capacity of DRAM. When the system clock frequency is
25 MHz, use DRAM chips having an access time of 60 ns or less.
The capacity of installed SIMMs can be detected using a PIO port. (See Section 6.1.2.)
3.12. ROM SOCKETS
The RTE-V821-PC has a ROM socket, which is used to hold 40-pin ROM chips to provide
standard 128 Kbytes (64K x16 bits). When the system clock frequency is 25 MHz, use ROM
chips having an access time of 150 ns or less.