NXP Semiconductors P87C654X2FA,529

Overview

P87C654X2FA,529 from NXP Semiconductors (formerly Philips Semiconductors) is a single-chip 8-bit microcontroller based on the 80C51 architecture, featuring 16 kB OTP ROM, 256 B RAM, and operation across 2.7–5.5 V. It supports both 6-clock and 12-clock modes (up to 30 MHz in 6-clock, 33 MHz in 12-clock), includes three 16-bit timers (T0/T1/T2), an enhanced UART with framing error detection, and four 8-bit I/O ports - enabling use in motor control systems requiring PWM, high-speed I/O, and up/down counting.

For engineers reviewing the P87C654X2FA,529 datasheet, P87C654X2FA,529 pinout, P87C654X2FA,529 application, or P87C654X2FA,529 equivalent, key selection criteria include OTP-based firmware immutability, dual data pointer support for external RAM expansion, low-power idle/power-down modes, and PLCC44 packaging with industrial temperature range (–40°C to +85°C).

Technical Context

The P87C654X2FA,529 implements a fully static CMOS 80C51-compatible CPU core with 100% instruction set compatibility and extended peripherals including Timer 2 with capture/compare capability, programmable clock-out on P1.0, and Fast I²C interface (SCL0/SDA0 on P1.6/P1.7). Its clock control register (CKCON) and factory-programmable OTP bit OX2 jointly govern 6-/12-clock mode selection - where OTP programming supersedes software-controlled X2 bit.

It integrates a watchdog timer, security bits (3-bit), 64-byte encryption array, and seven interrupt sources with four priority levels. Power management includes stop-clock, idle, and power-down modes - with wake-up from power-down via INT0/INT1 (level-sensitive), and retention of RAM/SFRs down to 2 V. ALE and PSEN behavior differs between idle and power-down per memory access type (internal/external), as defined in Table 2 of the datasheet.

Key Specifications

Pinout & Package

Package: PLCC44 (SOT187–2), plastic leaded chip carrier, 44-lead, industrial temperature range (–40°C to +85°C).

Key Features

Applications

Equivalent & Alternatives

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

Compared with P87C654X2FA,529, P83C654X2FA offers identical functionality at lower temperature grade, while P87C552FA sacrifices Timer 2 and I²C for cost reduction - making P87C654X2FA,529 optimal for new designs needing enhanced timing and interface flexibility in harsh environments.

Availability

P87C654X2FA,529 is available at Aetrix Electronics and suitable for motor control systems, industrial PLC I/O modules, energy metering front-ends, and legacy system upgrades requiring stable component supply and long-term lifecycle support.

Supply support for P87C654X2FA,529 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 semiconductor leader focused on secure connectivity solutions for automotive, industrial, and IoT applications.

The P87C654X2FA,529 belongs to the P8xC654X2 family - designed specifically for cost-sensitive, high-reliability embedded control applications demanding enhanced timing precision, low EMI, and OTP-based firmware security in industrial environments.

FAQ

What is the maximum operating frequency of the P87C654X2FA,529?

The P87C654X2FA,529 supports up to 30 MHz in 6-clock mode and 33 MHz in 12-clock mode at VCC = 5 V. Frequency scaling is governed by both the OTP-programmed OX2 bit and the software-configurable X2 bit in CKCON.0 - with OTP programming taking precedence. Operation below 2.7 V reduces maximum frequency per datasheet voltage-frequency curves.

Does the P87C654X2FA,529 support external memory expansion?

Yes, the P87C654X2FA,529 supports external memory expansion up to 64 kB ROM and 64 kB RAM using its multiplexed P0 (AD0–AD7) and P2 (A8–A15) buses. The dual data pointer (DPTR) feature enables efficient access to external RAM banks without software overhead - critical for real-time data buffering in motor control or metering applications.

How does the programmable clock-out function work on the P87C654X2FA,529?

The P87C654X2FA,529 can output a 50% duty cycle clock on P1.0 by configuring Timer 2 as a clock generator: clear C/T2 in T2CON, set T2OE in T2MOD, and enable TR2. Clock frequency depends on oscillator speed and RCAP2H/L values - ranging from 122 Hz to 8 MHz at 16 MHz operation (61 Hz to 4 MHz in 12-clock mode). Timer 2 roll-over does not generate interrupts in this mode.

What power-saving modes are available on the P87C654X2FA,529?

The P87C654X2FA,529 offers three low-power modes: stop-clock (CPU halted, peripherals active), idle (CPU stopped, RAM/SFRs retained, peripherals running), and power-down (oscillator halted, RAM/SFRs retained down to 2 V). Wake-up from power-down is supported via INT0/INT1 (level-sensitive) or hardware reset - with oscillator stabilization time <10 ms required before resuming execution.

Is the P87C654X2FA,529 pin-compatible with other 80C51-family microcontrollers?

The P87C654X2FA,529 uses a PLCC44 package with pin assignments aligned to standard 80C51 conventions for P0–P3, RST, XTAL1/XTAL2, VCC, and VSS. However, it adds dedicated functions on P1.0 (T2/clock-out), P1.1 (T2EX), P1.6 (SCL0), and P1.7 (SDA0) - meaning full pin compatibility exists only with other P8xC654X2 variants, not generic 80C51 devices.