NXP Semiconductors P87C54X2BBD,157

Overview

P87C54X2BBD,157 from NXP Semiconductors (formerly Philips) is a 16 KB OTP-based 8-bit microcontroller in the enhanced 80C51 family, operating at up to 33 MHz (12-clock mode) or 30 MHz (6-clock mode) across 2.7–5.5 V supply, featuring 256 B RAM, three 16-bit timers, full-duplex UART with framing error detection, and low-power idle/power-down modes - used in industrial control panels requiring deterministic real-time I/O handling and firmware-upgradable logic.

For engineers reviewing the P87C54X2BBD,157 datasheet, P87C54X2BBD,157 pinout, P87C54X2BBD,157 application, or P87C54X2BBD,157 equivalent, this page delivers verified package mapping (LQFP44), confirmed 6-/12-clock software-selectable operation, validated power-down wake-up via INT0/INT1, exact SFR register layout (including T2CON, CKCON, AUXR1), and direct substitution guidance against functionally aligned legacy 80C51 OTP variants.

Technical Context

This device implements a static CMOS 80C51 core with dual clock modes (6- or 12-clock per machine cycle), selectable via CKCON.X2 bit or OTP OX2 bit - enabling runtime speed doubling without hardware change. It integrates a programmable clock-out on P1.0 (61 Hz–8 MHz range), Timer 2 with capture/compare capability, and enhanced UART with automatic address recognition and framing error detection.

Power management includes hardware-supported idle mode (CPU halted, peripherals active) and power-down mode (oscillator stopped, RAM retained down to 2.0 V), with wake-up triggered by external interrupt (INT0/INT1) when WUPD bit is enabled in AUXR1. All I/O ports feature internal pull-ups and open-drain capability on Port 0.

Key Specifications

Pinout & Package

Package: LQFP44 (plastic low-profile quad flat package; 44 leads; body 10 × 10 × 1.4 mm; SOT389-1).

Key Features

Applications

Equivalent & Alternatives

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

Compared with P87C54X2FBD,157, the P87C54X2BBD,157 trades extended temperature rating for lower cost and identical functionality at 0–70 °C; versus P89C51RX2BN,518, it sacrifices Flash reprogrammability and I²C for proven OTP reliability and reduced BOM complexity in unchanging control logic.

Availability

P87C54X2BBD,157 is available at Aetrix Electronics and suitable for industrial PLC I/O modules, legacy equipment retrofit controllers, smart energy meter communication hubs, and automated test equipment sequencers requiring stable component supply and long-term obsolescence management.

Supply support for P87C54X2BBD,157 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 specializing in secure connectivity solutions for automotive, industrial, and IoT applications.

The P87C54X2BBD,157 belongs to the legacy 80C51 OTP microcontroller product line, designed for cost-sensitive, high-reliability embedded control applications where firmware immutability and long-term supply stability are critical.

FAQ

What is the maximum operating frequency of the P87C54X2BBD,157 and how does clock mode affect it?

The P87C54X2BBD,157 supports up to 33 MHz in 12-clock mode and 30 MHz in 6-clock mode at 5 V ±10%. The 6-clock mode halves the number of clock cycles per machine cycle, effectively doubling instruction throughput. This mode is selected either via the CKCON.X2 SFR bit (runtime configurable) or the OTP OX2 bit (set during programming). Both modes maintain full compatibility with standard 80C51 timing and instruction execution semantics.

Does the P87C54X2BBD,157 support external memory expansion, and what signals are used?

Yes, the P87C54X2BBD,157 supports external program and data memory expansion using its multiplexed Port 0 (AD0–AD7) and Port 2 (A8–A15) for address/data bus, along with dedicated control signals: PSEN (external program memory read strobe), ALE (address latch enable), RD (external data read), and WR (external data write). These signals conform to standard 80C51 bus timing, enabling seamless integration with SRAM, EPROM, or peripheral ICs without glue logic.

How does the power-down mode work on the P87C54X2BBD,157, and how is wake-up achieved?

In power-down mode, the P87C54X2BBD,157 stops the oscillator while retaining RAM and SFR contents down to 2.0 V. Wake-up is triggered by either a hardware reset or an external interrupt (INT0 or INT1), provided the WUPD bit in AUXR1 is set to 1. Upon wake-up, the oscillator restarts and stabilizes (typically <10 ms), after which execution resumes from the instruction following the one that initiated power-down - preserving full system context without software intervention.

Can the P87C54X2BBD,157 generate a precise clock output, and if so, on which pin and at what frequencies?

Yes, the P87C54X2BBD,157 can generate a precise 50% duty-cycle clock output on P1.0 using Timer 2 in clock-out mode. At 16 MHz oscillator frequency, the output ranges from 61 Hz to 4 MHz in 12-clock mode (122 Hz to 8 MHz in 6-clock mode), calculated as f_osc / [n × (65536 − RCAP2H:RCAP2L)], where n = 4 (12-clock) or 2 (6-clock). This eliminates need for external clock sources in timing-critical subsystems.

What are the key differences between the P87C54X2BBD,157 and the P89C51RX2 series?

The P87C54X2BBD,157 uses 16 KB OTP memory and targets fixed-function, cost-optimized applications with immutable firmware, while the P89C51RX2 series features 8 KB Flash memory enabling in-system reprogramming. The P89C51RX2 also adds I²C interface and enhanced interrupt vectoring, whereas the P87C54X2BBD,157 prioritizes proven reliability, wider voltage range (2.7–5.5 V), and long-term supply consistency for legacy industrial deployments.