MESA Electronic 4C24, Руководство пользователя

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CONNECTORS
POWER CONNECTOR
The 4C24 power connector (P2) is a 4 pin, single row, .1" header. The suggested mating
connector is an AMP MTA type connector 641190-4 (non-feedthrough) or 641198-4 (feedthrough).
These are both gold plated type connectors. Power pin arrangement is +5V, gnd, gnd, +5V. This pin-
out is compatible with newer (+5V only) 3.5 inch floppy drives.
Since the power connector on the 4C24 may power the whole PC104 stack, it is suggested that
only gold plated connectors be used. Tin plated connectors have a pronounced tendency to fail over
time via increased contact resistance when operated at anywhere near their rated current.
Power connector pinout is as follows:
PIN SIGNAL CURRENT RATING
1 +5V 1A
2 GND 1A
3 GND 1A
4 +5V 1A
The current ratings above mean that the total +5V current needs to be limited to 2A.
KEYBOARD CONNECTOR
P4 is the AT keyboard, reset-in and speaker connector. P4 is a 10 pin dual row 2mm header. The
suggested mating connector is Suyin20043-10G2 or 3M 152210-100-GG. This is an IDC (flat cable)
type connector. A keyboard adapter cable is available from MESA (The 4C24KBADPT).
An external reset switch input and speaker output are also available on P4. The reset circuit works
by grounding the /RESIN signal.
The speaker output is intended to drive high impedance speakers (40 ohms or more) . Eight Ohm
speakers will be too quiet for most applications. The speaker common is +5V. An external PNP
transistor can be used to drive an eight Ohm speaker to obnoxious volume levels if required.
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4C24 CPU USER'S MANUAL