NXP Semiconductors P89LPC902FN,129

Overview

P89LPC902FN,129 from NXP Semiconductors (formerly Philips) is an 8-bit microcontroller based on a two-clock 80C51 core, delivering six times the instruction throughput of standard 80C51 devices at the same frequency. It integrates 1 kB Flash code memory, 128-byte RAM, dual 16-bit timers, a 23-bit system/real-time clock, and two analog comparators - all in an 8-pin DIP package. It targets low-cost embedded control applications requiring compact footprint, internal oscillator operation, and keypad interrupt support.

For engineers reviewing the P89LPC902FN,129 datasheet, P89LPC902FN,129 pinout, P89LPC902FN,129 application, or P89LPC902FN,129 equivalent, key selection criteria include its dual-comparator architecture, five-keypad-interrupt capability, 2.4–3.6 V operation with 5 V-tolerant I/Os, and compatibility with In-Application Programming (IAP-Lite) for field firmware updates.

Technical Context

The P89LPC902FN,129 executes instructions in two to four clocks using an accelerated 80C51 CPU core, enabling 18 MHz operation with 111–222 ns instruction cycles. Its internal RC oscillator is factory-calibrated to ±1 % and supports frequencies from 20 kHz to 18 MHz without external components.

It features two independent analog comparators (CMP1 and CMP2), each with dedicated inputs and outputs, and supports programmable port configurations (quasi-bidirectional, open-drain, push-pull) across all I/O pins. Keypad interrupt detection operates on Port 0 pins with pattern-match logic and maskable inputs.

Key Specifications

Pinout & Package

Package: Plastic dual in-line package (DIP8), 300 mil body width (SOT97-1). Pin spacing and layout conform to industry-standard 8-pin DIP footprint.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit microcontroller applications.

Compared with P89LPC901FN,129 and P89LPC903FN,129, the P89LPC902FN,129 uniquely balances five-keypad support with dual analog comparators - making it optimal for cost-sensitive, sensor-augmented UIs where UART is not needed and higher key density is required.

Availability

P89LPC902FN,129 is available at Aetrix Electronics and suitable for home appliance control, industrial sensor interface, low-power remote controls, and embedded power supply monitoring requiring stable component supply and long-term manufacturability.

Supply support for P89LPC902FN,129 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

NXP Semiconductors (originally Philips Semiconductors) is a global leader in high-performance mixed-signal ICs, with deep expertise in 8-bit microcontrollers for cost-sensitive embedded systems.

The P89LPC90x family was designed specifically for ultra-compact, low-pin-count applications demanding integrated analog functions, keypad support, and minimal external components - targeting appliance, industrial, and consumer control markets.

FAQ

What is the maximum operating frequency of the P89LPC902FN,129?

The P89LPC902FN,129 supports a maximum CPU clock frequency of 18 MHz when using the internal RC oscillator or external crystal source. At this rate, instruction cycle times range from 111 ns to 222 ns - six times faster than a standard 80C51 running at the same clock. The device maintains full functionality including comparator operation, keypad interrupts, and IAP-Lite programming at 18 MHz.

Does the P89LPC902FN,129 support In-System Programming (ISP)?

Yes, the P89LPC902FN,129 supports In-System Programming via its built-in serial loader using the RST pin and Port 0 pins. This enables firmware updates without removing the device from the PCB. The P89LPC902FN,129 implements IAP-Lite functionality, allowing selective byte-erase and reprogramming of Flash memory while the application runs - critical for field upgrades and calibration data storage.

How many keypad interrupt inputs does the P89LPC902FN,129 provide?

The P89LPC902FN,129 provides five dedicated keypad interrupt inputs: KBI0, KBI2, KBI4, KBI5, and KBI6 - mapped to P0.0, P0.2, P0.4, P0.5, and P0.6 respectively. These inputs support maskable, edge-triggered interrupts and can be combined with port pattern-match logic to detect specific keypress combinations without continuous polling - reducing CPU load in UI-intensive designs.

Can the P89LPC902FN,129 operate without an external crystal?

Yes, the P89LPC902FN,129 operates fully without an external crystal thanks to its factory-calibrated internal RC oscillator (±1 % accuracy), configurable from 20 kHz to 18 MHz. When selected, this oscillator eliminates external timing components, reduces board space, and improves reliability - especially in cost-sensitive and high-volume applications like home appliances and remote controls.

What are the analog comparator capabilities of the P89LPC902FN,129?

The P89LPC902FN,129 integrates two independent analog comparators: CMP1 and CMP2. CMP1 uses CIN1A (P0.4) and CMPREF (P0.5) with output on P0.6; CMP2 uses CIN2A (P0.2) and CMPREF (P0.5) with output on P0.0. Both comparators support hysteresis control and generate digital outputs usable for interrupt generation or direct GPIO reading - enabling threshold-based decisions without ADC conversion.