AT&T PC 6300 - Input;Output Connectors

SYSTEM OVERVIEW ^
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Timer
The Timer is a programmable device that has three independent H
channels. Channel 0 is used as the input for the real-time clock. I J
Channel 1 is used to time and request refresh cycles from the
DMA channel. Channel 2 is used to support the tone generator for
the audio speaker. The timer used is the Intel 8253 (or equivalent)
programmable interval timer.
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Real-Time Clock and Calendar
A Clock-Calendar Chip is used to provide real time such as
seconds, minutes, hours, days, day of week, months, etc., for the
system. A 3-volt, low-power standby rechargeable battery is
connected to it to ensure that the real time is kept even when the
system is turned off. The chip used is the MM58174AN.
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Input/Output Connectors "|
There are five I/O Connectors on the Motherboard. Two of the ih
connectors (J1 and J2) are used to connect the Motherboard to the j
Display Controller. The other three connectors are for the
Keyboard, parallel interface (printer), and the asynchronous
RS-232 channel. The connectors, along with the signal (pin) |
names, are shown in Figure 2-6 as they appear on the '
Motherboard. Refer to the "AT&T Personal Computer 6300
Reference Manual" for detailed pin information.
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