NXP Semiconductors P87C52X2BN,112

Overview

P87C52X2BN,112 from Philips Semiconductors is an 8-bit OTP microcontroller based on the enhanced 80C51 architecture, featuring 8 KB on-chip OTP ROM, 256 B RAM, three 16-bit timers/counters (T0/T1/T2), full-duplex UART with framing error detection, and dual clock modes (6- or 12-clock). It operates from 2.7 V to 5.5 V and supports up to 33 MHz at 5 V in 12-clock mode - widely used in industrial control panels requiring reliable firmware storage and low-voltage operation.

For engineers reviewing the P87C52X2BN,112 datasheet, P87C52X2BN,112 pinout, P87C52X2BN,112 application, or P87C52X2BN,112 equivalent, key selection criteria include OTP-based firmware security, DIP40 package compatibility with legacy prototyping, 256-byte RAM for real-time interrupt handling, and support for both idle and power-down low-power modes in embedded monitoring systems.

Technical Context

This device implements a static CMOS 80C51 core with fully bit-addressable SFRs, dual data pointers, and four priority-level nested interrupts. Its T2 timer supports capture/compare and programmable clock-out functions, while the UART includes automatic address recognition and framing error detection - enabling robust multi-drop serial communication without external logic.

The CKCON register controls 6-/12-clock mode switching at runtime, and the AUXR/AUXR1 registers enable low-power EPROM operation (LPEP) and wake-up-from-power-down via INT0/INT1. Security bits (3 OTP bits) prevent unauthorized code readout, and the oscillator supports crystal, resonator, or external clock input via XTAL1/XTAL2.

Key Specifications

Pinout & Package

Package: Plastic Dual In-line Package (DIP40), 40-pin, 600 mil width, 0 °C to +70 °C operating range (SOT129-1).

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT89C52-24PU and P89C52X2BN,112, the P87C52X2BN,112 offers OTP-based firmware immutability ideal for certified medical/industrial devices, while retaining full 80C51 software compatibility and superior low-power features for battery-buffered operation.

Availability

P87C52X2BN,112 is available at Aetrix Electronics and suitable for industrial PLC I/O modules, legacy equipment retrofit controllers, and building automation sensor nodes requiring stable component supply and long-term obsolescence management.

Supply support for P87C52X2BN,112 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

Philips Semiconductors (now NXP Semiconductors) is a global semiconductor leader specializing in high-reliability mixed-signal ICs for industrial, automotive, and consumer applications.

The P87C5xX2 product line was designed specifically for cost-effective, pin-compatible upgrades of legacy 8051-based systems - emphasizing OTP security, wide voltage operation, and enhanced peripherals like T2 and programmable clock-out.

FAQ

What is the maximum operating frequency of the P87C52X2BN,112 at 3.3 V?

The P87C52X2BN,112 supports up to 16 MHz at any supply voltage from 2.7 V to 5.5 V in both 6-clock and 12-clock modes. At 3.3 V, this corresponds to 16 MHz (12-clock) or 16 MHz (6-clock), as the voltage-limited frequency ceiling is 16 MHz regardless of clock mode - verified in the "Operating Mode, Power Supply and Maximum External Clock Frequency" table on page 6 of the 2003 datasheet.

Does the P87C52X2BN,112 support in-system programming (ISP)?

No, the P87C52X2BN,112 uses One-Time Programmable (OTP) ROM and does not support in-system programming. Programming requires a parallel programmer with 12.75 V VPP applied to the EA/VPP pin (pin 20), as specified in the Pin Descriptions section (page 10) and confirmed in the Ordering Information tables. Firmware must be finalized before programming.

How does the P87C52X2BN,112 handle power-down wake-up events?

The P87C52X2BN,112 wakes from Power-down mode via hardware reset or enabled external interrupts (INT0 or INT1), provided WUPD bit (AUXR1.3) is set. Upon wake-up, the oscillator restarts and stabilizes (typically <10 ms), after which execution resumes from the instruction following the Power-down command - with all RAM and SFR contents preserved except on reset.

Can the P87C52X2BN,112's Timer 2 generate both a clock-out signal and serve as a baud-rate generator simultaneously?

Yes, the P87C52X2BN,112's Timer 2 can operate as both a clock-out generator and baud-rate generator concurrently. As stated on page 13, "It is possible to use Timer 2 as a baud-rate generator and a clock generator simultaneously", though both functions share the same frequency - meaning the UART baud rate and clock-out frequency will be identical in this configuration.

What is the function of the ALE/PROG pin on the P87C52X2BN,112 during normal operation?

During normal operation, the ALE/PROG pin (pin 30) outputs address latch enable pulses at 1/6 the oscillator frequency in 12-clock mode or 1/3 in 6-clock mode - providing a stable timing reference for external address latching in expanded memory systems. It can be disabled via SFR auxiliary.0 to reduce EMI, as documented in the Pin Descriptions section (page 10).