NXP Semiconductors P89C51RB2BA/01,512

Overview

P89C51RB2BA/01 from NXP Semiconductors (formerly Philips) is an 8-bit Flash microcontroller based on the 80C51 architecture, featuring 16 KB ISP/IAP Flash memory, 512 B RAM, four 8-bit I/O ports, three 16-bit timers, enhanced UART with framing error detection and automatic address recognition, and a programmable counter array (PCA) supporting PWM, capture, and compare functions - deployed in motor control and industrial embedded systems requiring high-speed I/O and up/down counting.

For engineers reviewing the P89C51RB2BA/01 datasheet, P89C51RB2BA/01 pinout, P89C51RB2BA/01 application, or P89C51RB2BA/01 equivalent, key selection criteria include 6-/12-clock mode configurability via Flash bit or SFR X2, peripheral clock independence in 6-clock CPU mode, 20 MHz / 33 MHz max frequency support at 5 V, PLCC-44 package compatibility, and boot ROM-based serial ISP capability without external loader code.

Technical Context

The P89C51RB2BA/01 implements a static CMOS 80C51 core with full instruction set compatibility and extends it with dual clock modes: default 12-clock operation (20 MHz max) or reprogrammable 6-clock mode (33 MHz max, 40 MHz equivalent performance). Its CKCON register enables independent 6-/12-clock selection per peripheral - including PCA, UART, Timer 2, Timer 1, and Timer 0 - while CPU runs in 6-clock mode.

This device integrates a 16 KB Flash program memory block with In-System Programming (ISP) and In-Application Programming (IAP) support, a dedicated boot ROM containing low-level Flash programming routines for UART-based ISP, and hardware features including asynchronous port reset, programmable clock-out on P1.0, second DPTR register, and low-EMI ALE inhibit. It supports four interrupt priority levels and seven interrupt sources.

Key Specifications

Pinout & Package

Package: PLCC-44 (SOT187-2), leaded chip carrier with 44 pins, surface-mount compatible, operating temperature range 0 °C to +70 °C, supply voltage 4.5 V to 5.5 V.

Key Features

Applications

Equivalent & Alternatives

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

Compared with P89C51RC2BA/01, the P89C51RB2BA/01 offers identical peripheral functionality at lower Flash density and cost, making it optimal for established designs with stable firmware footprints; versus AT89C51ED2-RL24PU, it retains critical industrial features like PCA-based PWM and UART auto-addressing but lacks USB - favoring legacy serial infrastructure and mechanical reliability.

Availability

P89C51RB2BA/01 is available at Aetrix Electronics and suitable for industrial motor control, smart energy metering, and embedded HVAC systems requiring stable component supply, long-term lifecycle support, and consistent PLCC-44 packaging.

Supply support for P89C51RB2BA/01 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 is a global semiconductor leader focused on secure connectivity solutions for automotive, industrial, and IoT applications, with heritage in Philips' IC division.

The P89C51RB2BA/01 belongs to the P89C51Rx2xx Flash microcontroller family, designed specifically for cost-sensitive, high-reliability embedded control applications where ISP/IAP, low-power modes, and 80C51 software compatibility are essential.

FAQ

What clock modes does the P89C51RB2BA/01 support, and how are they configured?

The P89C51RB2BA/01 supports both 6-clock and 12-clock modes. Default operation is 12-clock mode (20 MHz max). Configuration is achieved either via Flash bit FX2 (programmable through ISP or parallel programming) or dynamically using SFR bit X2 in CKCON register. When FX2 is programmed, it overrides the X2 bit setting. This dual configuration method ensures flexibility for both factory programming and runtime adaptation.

Does the P89C51RB2BA/01 support In-Application Programming (IAP), and what resources are required?

Yes, the P89C51RB2BA/01 supports IAP using ROM-resident Flash programming routines. These routines enable the user application to erase and reprogram Flash memory while the device remains operational - for example, updating firmware over a modem link. No external loader code is needed; only valid sector addresses, data buffers, and proper unlock sequences per the datasheet are required to initiate IAP.

What is the role of the Programmable Counter Array (PCA) in the P89C51RB2BA/01, and how many modules does it include?

The P89C51RB2BA/01 includes a five-module PCA supporting PWM generation, input capture, and software timers. Modules CEX0–CEX4 map to P1.3–P1.7 and operate independently with configurable trigger sources and modes. Each module can be used for edge-triggered capture of external events or for generating precise PWM waveforms - critical for motor control and signal timing applications.

Can the P89C51RB2BA/01's peripherals operate at different clock rates than the CPU, and which ones support this?

Yes - when the CPU runs in 6-clock mode, individual peripherals (PCA, UART, Timer 2, Timer 1, and Timer 0) can be configured via CKCON register bits (PCAX2, SIX2, T2X2, T1X2, T0X2) to use either fosc/6 or fosc/12. This allows, for instance, running the UART at full speed for high-baud-rate communication while keeping Timer 0 at slower rate for low-frequency event counting - all without changing CPU clock.

What package type and pin count does the P89C51RB2BA/01 use, and is it RoHS-compliant?

The P89C51RB2BA/01 uses a PLCC-44 package (SOT187-2), with 44 leads and a leaded chip carrier footprint. While the original 2002 datasheet predates RoHS legislation, current NXP-supplied units of P89C51RB2BA/01 meet RoHS Directive 2011/65/EU requirements. Aetrix Electronics guarantees only RoHS-compliant versions in active inventory and provides material declarations upon request.