Renesas R5F21236KFP#U1

Overview

R5F21236KFP from Renesas Electronics is a 16-bit R8C/23 Group microcontroller with CAN 2.0B interface, 32 KB program flash, 2 KB RAM, and 1 KB × 2 data flash-designed for automotive and industrial networking applications operating at -40°C to +125°C. It integrates a 10-bit 12-channel ADC, dual UARTs, LIN hardware module, I²C interface, and multiple timers including 16-bit Timer RD with input capture/output compare.

For engineers reviewing the R5F21236KFP datasheet, R5F21236KFP pinout, R5F21236KFP application, or R5F21236KFP equivalent, key selection criteria include its K-version extended temperature rating, on-chip CAN controller with 16 message slots, high-speed on-chip oscillator with frequency adjustment, and compatibility with Renesas' R8C development tools and emulator debugger infrastructure.

Technical Context

The R5F21236KFP implements the R8C 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 1 Mbyte address space, split between program ROM (32 KB), data flash (1 KB × 2), and RAM (2 KB), with dedicated SFR regions for CAN (01300h–0147Fh) and peripheral control.

Peripheral integration centers on real-time communication and sensing: one CAN 2.0B module with TX/RX pins (CTX0/CRX0), hardware LIN using Timer RA and UART0, dual UARTs (UART0/UART1), I²C bus interface, and 10-bit A/D converter with 12 analog inputs (AN0–AN11) referenced to internal VREF.

Key Specifications

Pinout & Package

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

Key Features

Applications

Equivalent & Alternatives

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

Compared with R5F21236JFP, the R5F21236KFP provides guaranteed operation up to +125°C for under-hood use, while R5F21237KFP offers 16 KB more program memory for feature-rich firmware-both retain identical peripheral sets, pinout, and debug infrastructure support.

Availability

R5F21236KFP is available at Aetrix Electronics and suitable for automotive body electronics, industrial CAN gateways, and motor drive monitoring systems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for R5F21236KFP 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 for automotive and industrial markets.

The R5F21236KFP belongs to the R8C/23 Group-a family of 16-bit MCUs engineered for cost-sensitive, real-time embedded control in harsh environments, emphasizing integrated CAN/LIN, robust flash reliability, and extended temperature operation.

FAQ

What is the maximum operating frequency of the R5F21236KFP?

The R5F21236KFP supports a maximum external clock frequency of 20 MHz on the XIN pin, achieving a minimum instruction execution time of 50 ns under 3.0–5.5 V supply conditions. Its high-speed on-chip oscillator can be adjusted up to 20 MHz but has ±2% accuracy over temperature-making it suitable for non-timing-critical subsystems where external crystal cost must be minimized. The R5F21236KFP maintains full functionality across its entire -40°C to +125°C operating range at this frequency.

Does the R5F21236KFP include hardware CAN or require external transceivers?

The R5F21236KFP integrates a complete CAN 2.0B protocol controller with 16 message buffers and all necessary logic for arbitration, error handling, and message filtering-but it does not include physical layer drivers. External CAN transceivers (e.g., TJA1042, SN65HVD230) must be used to connect CTX0 and CRX0 pins to the CAN bus. This separation allows design flexibility in selecting transceivers optimized for ESD immunity, fault protection, or low-power standby modes.

How is the data flash memory organized and accessed in the R5F21236KFP?

The R5F21236KFP contains two independent 1 KB data flash blocks located at memory addresses 02400h–027FFh and 02800h–02BFFh. These blocks support 10,000 write/erase cycles and are accessed via dedicated flash control registers (FCR, FASR) using command sequences defined in the hardware manual. Unlike program flash, data flash can be rewritten during normal operation without halting the CPU-enabling runtime parameter storage, calibration updates, and event logging without interrupting real-time tasks.

What debugging interfaces does the R5F21236KFP support?

The R5F21236KFP supports Renesas' standard on-chip debugging interface via the single-wire SWD (Serial Wire Debug) protocol using the RESET pin and optional dedicated debug pins. It is fully compatible with Renesas E1/E20 emulators and the CS+ IDE. Emulator debug resources occupy address range 20000h–23FFFh-this region must be excluded from application code and data placement. The R5F21236KFP also supports ROM monitor mode for bootloader development and field firmware updates.

Can the R5F21236KFP operate without an external crystal?

Yes-the R5F21236KFP includes a high-speed on-chip oscillator adjustable from 1 MHz to 20 MHz with ±2% accuracy over temperature and supply voltage, enabling crystal-free operation for non-timing-critical applications like LIN node control or sensor polling. For CAN, LIN, or UART timing compliance, however, an external crystal (e.g., 8 MHz or 16 MHz) connected to XIN/XOUT is required-since the on-chip oscillator's tolerance exceeds CAN bit timing error budgets. The R5F21236KFP automatically switches between oscillators based on system configuration.