Renesas CS82C54-12Z

Overview

CS82C54-12Z from Intersil is a CMOS programmable interval timer IC with three independent 16-bit counters, supporting up to 12MHz clock input frequency, binary or BCD counting, six programmable modes, and TTL-compatible 5V operation - used for real-time clock generation, event counting, and programmable rate control in legacy x86 embedded systems.

For engineers reviewing the CS82C54-12Z datasheet, CS82C54-12Z pinout, CS82C54-12Z application, or CS82C54-12Z equivalent, this page delivers verified timing parameters, PLCC-28 package mapping, counter mode behavior, status read-back capability, and direct alternatives for industrial control and retro-computing designs requiring drop-in NMOS 8254 compatibility.

Technical Context

The CS82C54-12Z implements three fully independent 16-bit synchronous down counters, each configurable via an 8-bit control word specifying mode (0–5), count format (binary/BCD), and read/write sequence. Its static CMOS architecture enables low-power operation (10µA standby) while maintaining full TTL signal compatibility and precise timing control across all modes.

It supports hardware-triggered operations via GATE inputs, software-controlled latching via Counter Latch and Read-Back commands, and dual-byte count transfers synchronized to CLK edges - enabling deterministic timing in interrupt-driven and polled I/O architectures without CPU overhead.

Key Specifications

Pinout & Package

CS82C54-12Z is housed in a 28-lead PLCC (Plastic Leaded Chip Carrier) package, RoHS-compliant with matte tin termination, suitable for surface-mount reflow assembly.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar programmable timer applications.

Compared with CS82C54-10Z and Intel 8254-2, the CS82C54-12Z offers highest timing resolution (83.3ns), lowest standby power (10µA), and enhanced diagnostics (read-back command), making it optimal for modernized retro systems and power-constrained industrial timers requiring guaranteed 12MHz operation.

Availability

CS82C54-12Z is available at Aetrix Electronics and suitable for industrial motion control, legacy PC peripheral timing, embedded data acquisition, and retrocomputing hardware emulation requiring stable component supply and long-term lifecycle support.

Supply support for CS82C54-12Z includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Intersil Corporation was a U.S.-based semiconductor company specializing in high-performance analog and mixed-signal ICs, later acquired by Renesas Electronics in 2017.

The 82C54 family was designed as a CMOS-enhanced, drop-in replacement for the Intel 8254, targeting power-efficient, timing-critical embedded systems requiring full software compatibility with legacy x86 and 8051 architectures.

FAQ

What is the maximum clock frequency supported by the CS82C54-12Z?

The CS82C54-12Z supports a maximum clock input frequency of 12MHz, as confirmed in the AC Electrical Specifications table (TCLK min = 80ns). This enables timing resolution down to 83.3ns per clock cycle and distinguishes it from the -10Z (10MHz) and base 82C54 (8MHz) variants. The 12MHz rating applies to all three counters independently and is validated across the full 0°C to +70°C operating range.

Does the CS82C54-12Z support BCD counting, and how is it configured?

Yes, the CS82C54-12Z supports Binary-Coded Decimal (BCD) counting via the BCD bit (D0) in the Control Word Register. When set to '1', the selected counter operates in 4-decade (0000–9999) BCD mode; when '0', it runs as a 16-bit binary counter. This setting is per-counter and persists until reprogrammed. BCD mode is essential for decimal timekeeping applications such as real-time clocks with direct 7-segment display interfacing.

How does the Status Read-Back command work in the CS82C54-12Z?

The Status Read-Back command (Control Word D7–D4 = 1100) allows software to read the current state of the OUT pin, Null Count flag, and programmed mode bits for any or all three counters. It is issued by writing to the Control Word Register with SC1/SC0 selecting the target counter(s) and D3–D1 enabling specific counters. The latched status byte (D7 = OUT, D6 = Null Count, D5–D0 = Mode) is then read back from the corresponding counter's data port, enabling non-intrusive runtime diagnostics.

Is the CS82C54-12Z pin-compatible with the original Intel 8254?

Yes, the CS82C54-12Z is fully pin-compatible with the Intel 8254 in its PLCC-28 package variant, matching pin functions, electrical levels, and timing sequences. The datasheet explicitly states "Compatible with NMOS 8254" and confirms identical pinout for PLCC configurations. No PCB layout changes are required when upgrading from 8254 to CS82C54-12Z, provided the system operates within the 0°C to +70°C range and uses 5V ±10% supply.

What power supply requirements does the CS82C54-12Z have?

The CS82C54-12Z requires a single +5V supply with a specified operating range of +4.5V to +5.5V (±10%). It draws 10mA typical operating current at 8MHz and only 10µA in standby mode. A 0.1µF ceramic decoupling capacitor between VCC and GND is mandatory per the datasheet to suppress switching noise and ensure stable counter operation under load.