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8279/8279·5
PROGRAMMABLE KEYBOARD/DISPLAY INTERFACE
• MCS·85™ Compatible 8279·5
• Simultaneous Keyboard Display
Operations
• Scanned Keyboard Mode
• Scanned Sensor Mode
• Strobed Input Entry Mode
• 8·Character Keyboard FIFO
• 2·Key Lockout or N·Key Rollover with
Contact Debounce
• Dual
8·
or 16·Numerical Display
• Single 16·Character Display
• Right or Left Entry 16·Byte Display
RAM
• Mode Programmable from
CPU
• Programmable Scan Timing
• Interrupt Output on Key Entry
The Intel'"
8279
is a general purpose programmable keyboard and display
1/0
interface device designed for use with
Intel'" microprocessors. The keyboard portion can provide a scanned interface to a 64-contact key matrix.
The
keyboard portion will also Interface to
an
array
of
sensors or a strobed Interface keyboard, such
as
the hall effect and
ferrite variety. Key depressions can
be
2·key lockout or N-key rollover. Keyboard entries are debounced and strobed in
an
8-character FIFO. If more than 8 characters are entered, overrun status is set. Key entries set the interrupt output
line to the
CPU.
The display portion provides a scanned display interface for
LED,
incandescent,
and
other popular display
technologies. Both numeric and alphanumeric segment displays
may
be
used
as
well
as
simple indicators.
The
8279
has
16X8
display
RAM
which can be organized into dual
16X4.
The
RAM
can
be
loaded or interrogated
by
the
CPU.
Both
right entry, calculator and left entry typewriter
display formats
are
possible. Both read and write
of
the display
RAM
can be done with auto-increment
of
the display
RAM
address.
PIN CONFIGURATION
our A,
qUT
A2
OUT
A3
Bl!
cs
PIN
NAMES
CPU
INTERFACE
l
9-70
LOGIC SYMBOL
Vee
IRQ
RLa.1
DATA
BUS
SHIFT
RD
WR
CNTL'STB
CS
SlO.3
AO
OUT
AO-J
RESET
ClK
our B0-3
VIS
- KEY
DATA
SCAN
DISPLAV
DATA
AFN-D0742A-Ol