Product Overview
Intel P8279 Keyboard and Display Interface in a 40-Pin Plastic DIP
Condition
Working pull from lightly used lab equipment. The topside ink panel reads P8279 over the lot line L9370845, with the Intel lowercase i logo and the mask copyright mark INTEL '76 below it. The reverse of the body carries a second ink panel reading 49310070 and AA CDL35, with two moulded dimples flanking it. All 40 leads are present, straight, evenly spaced and bright, with no solder residue and no bent or clipped pins, which is what a socket-pulled part looks like. The grey plastic body shows only light handling marks. It is sold as a working pull, graded on that basis and on the visual inspection shown in these photographs; no functional test data is published with this listing, and the photos are the spec for this piece.
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Product Overview
The Intel 8279 is a programmable keyboard and display interface: a dedicated peripheral chip that takes two tedious jobs off the processor by scanning a key matrix, debouncing and buffering the keystrokes it finds, and refreshing a multiplexed digit or character display from its own internal RAM. It was designed for the Intel MCS-80 and MCS-85 microprocessor families and turns up wherever an 8-bit board needed a front panel without burning CPU time on it. This piece is the plastic-package version, the P prefix in Intel's own nomenclature, in the 40-pin dual in-line footprint. Specific timing, voltage, key-matrix and display-RAM figures are not confirmed here - verify them against the Intel 8279 datasheet before designing it in.
Key Features
- Part marking: P8279, with the Intel logo and the mask copyright INTEL '76
- Lot marking as photographed: L9370845 topside, 49310070 and AA CDL35 on the reverse
- Package: 40-pin plastic dual in-line (PDIP40), leads straight and bright
- Function: programmable keyboard scanning and multiplexed display refresh
- Designed for the Intel MCS-80 and MCS-85 8-bit microprocessor families
- Brand: Intel
- Quantity: one piece in stock, and it is the exact chip photographed
- Test status: sold as a working pull from lightly used lab equipment, no published test data
Applications
- A retrocomputing hobbyist rebuilding an 8085 single-board trainer that lost its keypad and seven-segment display controller
- A maintenance technician keeping a 1980s instrument front panel alive when the original keyboard interface finally quits
- A collector matching an original build exactly and wanting the period-correct Intel plastic part rather than a modern substitute
- An electronics instructor assembling a bench demonstration of hardware key scanning and display multiplexing
Frequently Asked Questions
What does the 8279 actually take off my processor?
Two things: the key matrix scan, including debounce and a small keystroke buffer, and the refresh of a multiplexed display driven from its own display RAM. The processor reads and writes it over the 8-bit bus instead of bit-banging the panel itself. Exact matrix size, buffer depth and display RAM organization are not confirmed here - check the Intel 8279 datasheet.
Does the '76 marking mean this chip was made in 1976?
No. INTEL '76 next to the logo is the mask copyright year for the design, not the manufacturing date of this individual piece. The other strings on the body - L9370845 topside, 49310070 and AA CDL35 on the reverse - are Intel lot and trace markings. We are not decoding a manufacturing date from them and neither should you.
Is this the ceramic or the plastic version?
Plastic. The P prefix in P8279 is Intel's plastic-package designation, and the photographs show the grey plastic 40-pin dual in-line body with the ink-printed marking panel. If your build specifically calls for the ceramic C8279 or an extended-temperature grade, this is not that part.
This is a pull from lab equipment - what am I actually taking on?
You are getting the single chip in these three photographs, described honestly: pulled working from lightly used lab equipment, leads straight and bright, body markings fully legible, and no functional test data published alongside it. Socket rather than solder is the sensible way to put a part like this into a board, so you can confirm it in circuit and swap it if your fault turns out to live somewhere else. Nothing else is implied and nothing else is included. Shipping is $8 flat rate and free once your order passes $28, so this one is worth pairing with the rest of your bench list, and orders leave our Idaho warehouse the same or next business day.
Somebody once decided a processor had better things to do than count key bounces, and the 8279 has been quietly doing that dull job ever since. If a panel of buttons and digits has gone dark on a board you are trying to save, this is the chip that used to run it.
