D82542

The D82542 is the 10 MHz grade of Intel's 8254 Programmable Interval Timer, the faster "-2" bin that handles clock inputs from DC all the way to 10 MHz. The "D" prefix marks a 24-pin CERDIP, a hermetic ceramic package well suited to long-life industrial and legacy systems. Built in HMOS and running from a single +5V supply, it packs three fully independent 16-bit counters that offload timing and counting work from the host CPU. It is a superset of the earlier 8253 and interfaces with Intel and most other microprocessors as a simple array of I/O ports.

Key Features

• Three independent 16-bit counters - each counter runs its own mode and count, giving a design three separate timing channels in one package.
• 10 MHz operation - the 8254-2 accepts clock inputs up to 10 MHz, with a 100 ns minimum clock period for the tightest timing resolution in the family.
• Six programmable modes - interrupt on terminal count, hardware retriggerable one-shot, rate generator, square wave, software strobe, and hardware strobe cover most timing tasks.
• Binary or BCD counting - each counter can be programmed for 16-bit binary or 4-decade BCD, selected in software per channel.
• Status read-back command - the CPU can latch count and status, including the OUT pin state and null-count flag, without disturbing a count in progress.
• Single +5V HMOS design - one supply rail and a standard 0°C to 70°C range keep board integration straightforward.

Typical Applications

• Real-time clock and system tick - the rate generator mode produces periodic interrupts for timekeeping and scheduler ticks.
• Baud rate and waveform generation - square wave mode supports serial baud clocks and other periodic signals.
• Event counting and motor control - independent counters handle event tallies, digital one-shots, and complex motor timing.

Unique Advantages

• Top speed grade - at 10 MHz the D82542 is the fastest 8254 variant, so it can replace an 8 MHz 8254 in a design without losing timing headroom.
• Hermetic CERDIP - the ceramic package tolerates harsher thermal and humidity conditions than plastic, a fit for long-service equipment.
• Drop-in 8253 upgrade - as a superset of the 8253, it preserves software compatibility while adding the read-back command.

Why Choose D82542?

Engineers reach for the D82542 when a legacy or industrial design needs the full 10 MHz 8254 timer in a rugged ceramic package that holds up over a long production life. Its three independent counters, six modes, and read-back command cover timing, counting, and waveform jobs that would otherwise burden the processor. Decades of use across x86 and embedded systems make its behavior well understood and easy to port.

Contact us for current pricing, stock, and lead time on the D82542, and ask about continuing-source availability for long-lifecycle builds.