Renesas R4F24256NFAU

Overview

R4F24256NFAU from Renesas Electronics is a 16-bit single-chip microcontroller in the H8S/2425 Group, featuring 256 KB on-chip Flash memory, 16 KB RAM, and integrated peripherals including TPU, SCI, WDT, and CPG. It operates at up to 33 MHz, supports 5 V operation, and targets industrial control and embedded instrumentation applications requiring deterministic real-time response.

For engineers reviewing the R4F24256NFAU datasheet, R4F24256NFAU pinout, R4F24256NFAU application, or R4F24256NFAU equivalent, key selection criteria include Flash endurance (10,000 write/erase cycles), operating temperature range (−40°C to +85°C), 100-pin LQFP package compatibility, and support for H8S/2400-series instruction set compatibility and peripheral register mapping.

Technical Context

The R4F24256NFAU implements the H8S/2400 CPU core with 24-bit address space, advanced mode support, and dual-stack architecture. It integrates a programmable clock pulse generator (CPG) supporting internal oscillator, external crystal, or external clock input with PLL multiplication, enabling flexible system clock configuration from 1 to 33 MHz.

Peripheral subsystems include a 16-bit Timer Pulse Unit (TPU) with 8 channels, two Serial Communication Interfaces (SCI) supporting asynchronous and clock-synchronous modes, and a watchdog timer with independent reset and interrupt capability. Memory protection is enforced via on-chip bus controller (BSC) and memory-mapped I/O addressing.

Key Specifications

Pinout & Package

Package: 100-pin LQFP (14 mm × 14 mm, 0.5 mm pitch), RoHS-compliant, moisture sensitivity level (MSL) 3.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 16-bit microcontroller applications.

Compared with R4F24256NFAU, R4F24256NFAV offers extended temperature operation at identical price point for mission-critical deployments, while R4F24252NFAU provides hardware-compatible cost reduction where memory headroom permits - both retain full register-level compatibility and toolchain support.

Availability

R4F24256NFAU is available at Aetrix Electronics and suitable for industrial automation, motor control, and energy metering applications requiring stable component supply, long-term lifecycle assurance, and consistent 5 V embedded design compatibility.

Supply support for R4F24256NFAU 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

Renesas Electronics Corporation is a global semiconductor leader headquartered in Japan, specializing in microcontrollers, analog, power, and SoC solutions for industrial, automotive, and infrastructure markets.

The H8S/2425 Group - including R4F24256NFAU - was designed for deterministic real-time control in cost-sensitive industrial equipment, emphasizing robust 5 V operation, Flash endurance, and peripheral integration without external glue logic.

FAQ

What is the maximum system clock frequency supported by the R4F24256NFAU?

The R4F24256NFAU supports a maximum system clock frequency of 33 MHz. This is achieved using the on-chip PLL with an external crystal (1–8 MHz) or external clock source. The PLL allows multiplication up to ×4, and the CPG module ensures stable clock distribution across CPU and peripherals. At 33 MHz, the R4F24256NFAU delivers approximately 20 MIPS performance, sufficient for real-time control loops with sub-10 µs interrupt latency.

Does the R4F24256NFAU include hardware debugging support?

Yes, the R4F24256NFAU integrates a full on-chip debug system (OCDS) compliant with Renesas' standard debug protocol. It supports breakpoints, watchpoints, real-time trace, and single-step execution via dedicated debug pins (BKGD, RES, and optional TRACES). No external JTAG emulator is required - standard Renesas E1/E20 debuggers connect directly. This capability is active across all operating modes, including HALT and STOP.

What is the Flash memory endurance specification for the R4F24256NFAU?

The R4F24256NFAU specifies 10,000 write/erase cycles for its 256 KB on-chip Flash memory, with guaranteed data retention of 20 years at +85°C. Each erase operation targets 128-byte blocks, and programming is performed in 2-byte (word) units. The Flash controller includes built-in error detection and automatic erase verification, ensuring reliability in field-upgrade scenarios typical of industrial firmware updates.

Can the R4F24256NFAU operate from a 3.3 V supply?

No, the R4F24256NFAU is specified exclusively for 4.5 V to 5.5 V operation and is not 3.3 V tolerant. Its I/O structure, internal regulators, and Flash programming voltage require nominal 5 V. Interfacing with 3.3 V peripherals requires level-shifting circuitry or voltage translators. Attempting 3.3 V supply will result in undefined behavior, failed Flash writes, and potential register corruption due to insufficient VCC margin for internal logic thresholds.

How many serial communication interfaces does the R4F24256NFAU provide?

The R4F24256NFAU integrates two independent Serial Communication Interfaces (SCI0 and SCI1), each supporting asynchronous (UART) and clock-synchronous (SPI-like) modes. Both SCIs feature programmable baud rate generators, 8- or 9-bit data framing, parity control, and FIFO buffering (2-byte receive/transmit). They can be configured for RS-232, RS-485 (with external transceiver), or proprietary serial protocols without external components.