IBM XT 5160 User Manual

-I/O cn CK (I)
-I/O Channel Check: This line provides the microprocessor with
parity (error) information
on memory or devices in the I/O
channel. When this signal is active low, a parity error is indicated.
I/O cn RDY (I)
I/O Channel Ready: This line, normally high (ready), is pulled
low (not ready)
by a memory or I/O device to lengthen I/O or
memory cycles. It allows slower devices to attach to the I/O
channel with a minimum of difficulty. Any slow device using this
line should drive it low immediately upon detecting a valid address
and a
Read or Write command. This line should never be held
low longer
than 10 clock cycles. Machine cycles (I/O or
memory) are extended by an integral number of clock cycles
(210ns).
-lOR (0)
-I/O Read Command: This command line instructs an I/O
device to drive its data onto the data bus. It may be driven by the
microprocessor
or the DMA controller. This signal is active low.
-lOW (0)
-I/O Write Command: This command line instructs an I/O
device to read the data on the data bus. It may be driven by the
microprocessor
or the DMA controller. This signal is active low.
IRQ2-IRQ7 (I)
Interrupt Request 2 to 7: These lines are used to signal the
microprocessor
that an I/O device requires attention. They are
prioritized with
IRQ2 as the highest priority and IRQ7 as the
lowest.
An interrupt request is generated by raising an IRQ line
(low to high) and holding it high until it
is acknowledged by the
microprocessor (interrupt service routine).
1-22 System Board

IBM XT 5160 Specifications

General

Brand	IBM
Model	XT 5160
Category	Desktop
Language	English