Renesas R5F21238JFP#U1

Overview

R5F21238JFP from Renesas Electronics is a 16-bit R8C/23 Group microcontroller featuring the R8C CPU core, 64 KB flash program memory, 3 KB RAM, and embedded 2 KB data flash (1 KB × 2 blocks). It integrates a CAN 2.0B module (16-message buffer), 12-channel 10-bit A/D converter, dual UARTs, I²C bus interface, hardware LIN, and multiple timers-including two 16-bit timer RD channels with input capture/output compare-targeting automotive body control and industrial FA networking applications.

For engineers reviewing the R5F21238JFP datasheet, R5F21238JFP pinout, R5F21238JFP application, or R5F21238JFP equivalent, this MCU delivers deterministic real-time control with CAN+LIN coexistence, on-chip voltage detection and power-on reset, -40°C to +85°C operation, and LQFP-48 packaging compatible with standard surface-mount assembly processes.

Technical Context

The R5F21238JFP implements the R8C 16-bit CISC CPU core with 89 fundamental instructions and executes at 50 ns minimum instruction time (20 MHz XIN, 3.0–5.5 V). Its memory architecture includes unified 1 Mbyte address space, split between program ROM (64 KB), data flash (2 KB), and SRAM (3 KB), with dedicated SFR areas for CAN (01300h–0147Fh) and peripheral control.

Peripheral integration centers on deterministic communication and sensing: one CAN 2.0B controller with 16-slot message RAM, dual UARTs (UART0 with LIN support via Timer RA, UART1 standalone), I²C master/slave, 12-channel 10-bit SAR ADC with internal reference options, and four independent timer modules (RA/RB/RE: 8-bit; RD: 16-bit ×2 with prescaler and capture/compare).

Key Specifications

Pinout & Package

Package: 48-pin plastic LQFP (PLQP0048KB-A), 7 mm × 7 mm body, 0.5 mm pin pitch, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with R5F21238KFP, the R5F21238JFP trades extended temperature range for lower cost and qualification effort in cabin applications; compared with R5F21228JFP, it adds 2 KB of data flash for robust in-field calibration and fault logging without external components.

Availability

R5F21238JFP is available at Aetrix Electronics and suitable for automotive body electronics, industrial fieldbus nodes, and smart HVAC actuation requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for R5F21238JFP 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 formed in 2010 through the merger of NEC Electronics and Renesas Technology, specializing in microcontrollers, analog, and power solutions.

The R8C/23 Group, including R5F21238JFP, was designed for cost-sensitive, real-time automotive and industrial control applications requiring integrated CAN, LIN, and analog interfaces in compact LQFP packages.

FAQ

What is the maximum operating frequency of the R5F21238JFP?

The R5F21238JFP supports a maximum external crystal frequency of 20 MHz, enabling a minimum instruction execution time of 50 ns under 3.0–5.5 V supply conditions. Its high-speed on-chip oscillator is adjustable from 1–20 MHz, providing flexibility for applications where external crystals are undesirable. The R5F21238JFP maintains full peripheral functionality-including CAN and ADC-at this maximum frequency.

Does the R5F21238JFP include on-chip debugging support?

Yes, the R5F21238JFP includes on-chip debugging circuitry compatible with Renesas E8/E8a emulators. Debug access uses dedicated pins (including MODE and RESET) and reserves address ranges 20000h–23FFFh for emulator use-these addresses must not be used by application code. The R5F21238JFP supports breakpoints, watchpoints, and real-time variable monitoring without requiring external JTAG hardware.

How is the data flash organized in the R5F21238JFP?

The R5F21238JFP contains 2 KB of data flash, implemented as two independent 1 KB blocks located at memory addresses 02400h–027FFh and 02800h–02BFFh. Each block supports 10,000 erase/write cycles and can be programmed/erased separately under VCC = 2.7–5.5 V. This structure allows wear leveling and safe parameter storage in the R5F21238JFP without affecting program ROM integrity.

Can the R5F21238JFP operate from a 3.3 V supply?

Yes, the R5F21238JFP operates over a supply range of 3.0 V to 5.5 V, making it fully compatible with 3.3 V systems. At 3.3 V, the maximum supported XIN frequency is reduced to approximately 13 MHz (per Renesas electrical characteristics derating), but all peripherals-including CAN, UARTs, and ADC-remain functional. The R5F21238JFP's voltage detection circuit can be configured to monitor 3.3 V rails directly.

What peripheral modules share pins with general-purpose I/O on the R5F21238JFP?

Multiple peripherals share pins with GPIO on the R5F21238JFP, including CAN (CTX0/CRX0), UART (RXD0/TXD0, RXD1/TXD1), I²C (SCL/SDA), LIN (RXD0 with Timer RA), and ADC (AN0–AN11). Pin function selection is controlled via peripheral enable bits and port mode registers-enabling a peripheral automatically overrides the corresponding GPIO function. The R5F21238JFP requires careful pin multiplexing planning during schematic design to avoid conflicts.