Looks like no one added any tags here yet for you.
Variable address
The 16-bit I/O address in DX is called
Fixed address
Intel calls the 8-bit form (p8) a__because it is stored with the instruction, usually in a ROM
Port number (or simply port
Whenever data are transferred by using the IN or OUT instructions,
the I/O address, often called a
Isolated I/O
the IN, INS, OUT, and OUTS instructions transfer data between the
microprocessor's accumulator or memory and the I/O device
Memory-mapped I/O
any instruction that references memory can accomplish the
transfer
Isolated
describes how the I/O locations are isolated from the memory
system in a separate I/O address space
Basic input device
Is a set of three-state buffers
handshaking or polling
Another method of I/O control, called__synchronizes the I/O
device with the microprocessor
Programmable peripheral interface (PPI
is a very popular, low-cost interfacing component found in many applications
Stepper motor
is a digital motor because it is moved in discrete steps as it traverses through 360
Bidirectional bus
is used by referencing port A with the IN and OUT instructions
modem
which is a device that converts TTL levels of serial data into audio tones that can pass through the telephone system
16550
programmable communications interface, capable of receiving and transmitting
asynchronous serial data
DAC0830
is an 8-bit digital-to-analog converter that converts a digital signal to an analog voltage within 1.0 µs
ADC0804
is an 8-bit analog-to-digital converter that converts an analog signal into a digital signal within 100 με
strobe
input loads data into the port latch, which holds the information until it is input to the microprocessor via the IN instruction.
Input buffer full (IBF)
is an output indicating that the input latch contains information
Interrupt request
pin becomes a logic 1 when the STB input returns to a logic 1, and is cleared when the data are input from the port by the microprocessor.
interrupt
enable signal is neither an input nor an output; it is an internal bit programmed via the port PC4 (port A) or PC2 (port B) bit position.
Output buffer full (obf)
This signal is set to a logic 1 whenever the ack pulse returns from the external device.
acknowledge signal
signal is a response from an external device, indicating that it has received the data from the 82C55 port.
Interrupt request
is an output used to interrupt the microprocessor for both input and output conditions.
clock
input is the timing source for each of the internal counters.
Chip select
enables the 8254 for programming and reading or writing a counter
counter outpu
is where the waveform generated by the timer is available.
MODE0
the output becomes a logic 0 when the control word is written and remains there until N plus the number of programmed counts.
MODE 1
Causes the counter to function as a retriggerable, monostable multivibrator (one-shot).
MODE 2
Allows the counter to generate a series of continuous pulses that are one clock pulse wide
MODE 3
Generates a continuous square wave at the OUT connection, provided that the G pin is a logic 1.
MODE 4
Allows the counter to produce a single pulse at the output. If the count is programmed as a 10, the output is high for 10 clocking periods and low for one clocking period.
MODE 5
A hardware triggered one-shot that functions as mode 4, except that it is started by a trigger pulse on the G pin instead of by software.
address strobe
input is used to latch the address lines and chip select lines
baud out
pin is where the clock signal generated by the baud rate gen erator from the transmitter section is made available.
clear-to-send
This pin is often used in a half-duplex system to turn the line around
data carrier detect
input is used by the modem to signal the 16550 that a carrier is present.