RX261 Evaluation Kit

Overview

The EK-RX261 is an Evaluation Kit for the Renesas RX261 MCU Group, designed to evaluate features of the RX261 family and accelerate embedded system development. The board includes rich interfaces, peripheral connectors, and expansion support for popular ecosystem modules.

The key features of the EK-RX261 board are categorized in three groups:

MCU Native Pin Access

RX261 MCU (R5F52618BGFP), 32-bit RXv3 core at 64MHz
512KB Code Flash, 8KB Data Flash, 128KB RAM
Native pin access through 6 x 2-pin and 14 x 2-pin x 3-piece male headers
MCU current measurement points for current consumption measurement
Precision 8.000MHz main oscillator and 32.768kHz sub-clock

System Control and Ecosystem Access

Four 5V input sources:
- USB (USB DEBUG1, USB FULL SPEED, USB SERIAL)
- External power supply (via TP5, TP6)
Two Debug Modes:
- Debug on-board via E2 Emulator OB (FINE interface)
- Debug in via 14-pin external header (FINE interface)
User LEDs:
- 3 User LEDs (Red, Green, Blue)
- 1 Power LED (White)
- 1 Debug LED (Yellow)
User Buttons:
- 2 User Switches
- 1 Reset Switch
Popular ecosystem expansion connectors:
- 2x Grove connectors (I2C / Analog)
- 1x SparkFun Qwiic connector (I2C)
- 2x Digilent Pmod connectors (UART/SPI/I2C)
- Arduino Uno R3-compatible header
- mikroBUS connector
USB Full Speed Host and Device (micro-B connector)
USB to Serial communication via FT234XD

Special Feature Access

CAN FD transceiver with 3-pin header
Touch interface (2 buttons)

Hardware

Detailed hardware features can be found at:

RX261 MCU: RX261 Group User’s Manual Hardware.
EK-RX261 board: EK-RX261 - User’s Manual.

Supported Features

The ek_rx261 board supports the hardware features listed below.

on-chip / on-board: Feature integrated in the SoC / present on the board.
2 / 2: Number of instances that are enabled / disabled.
Click on the label to see the first instance of this feature in the board/SoC DTS files.
vnd,foo: Compatible string for the Devicetree binding matching the feature.
Click on the link to view the binding documentation.

`ek_rx261/r5f52618bgfp` target

Type	Location	Description	Compatible
CPU	on-chip	Renesas RXv3 CPU1	`renesas,rxv3`
ADC	on-chip	Renesas RX ADC1	`renesas,rx-adc`
Clock control	on-chip	Renesas RX Root Clock Generation Circuit3 2	`renesas,rx-cgc-root-clock`
	on-chip	Renesas RX Clock Generation Circuit PLL Clock1 1	`renesas,rx-cgc-pll`
	on-chip	Renesas RX clock control node pclk block1	`renesas,rx-cgc-pclk-block`
	on-chip	Renesas RX Clock Control Peripheral Clock5 12	`renesas,rx-cgc-pclk`
Flash controller	on-chip	Renesas RX Flash controller1	`renesas,rx-flash`
GPIO & Headers	on-chip	Renesas RX series GPIO5 8	`renesas,rx-gpio`
I2C	on-chip	Renesas RX I2C Master controller1	`renesas,rx-i2c`
Input	on-board	Group of GPIO-bound input keys1	`gpio-keys`
Interrupt controller	on-chip	Renesas ICU Interrupt controller1	`renesas,rx-icu`
LED	on-board	Group of GPIO-controlled LEDs1	`gpio-leds`
Miscellaneous	on-chip	Renesas RX Data Transfer Controller (DTC)1	`renesas,rx-dtc`
	on-chip	Renesas RX External Interrupt2 6	`renesas,rx-external-interrupt`
	on-chip	Renesas RX SCI controller1 3	`renesas,rx-sci`
MTD	on-chip	Flash memory binding of Renesas RX family2	`renesas,rx-nv-flash`
MTD	on-board	Fixed partitions of a flash (or other non-volatile storage) memory1	`fixed-partitions`
Pin control	on-chip	Renesas RX Pin Controller1	`renesas,rx-pinctrl`
Pin control	on-chip	Rensas RX Pinmux (Multi Function Pin Controller, MPC)13	`renesas,rx-pinmux`
Renesas RX	on-chip	Renesas RX SWINT (Software Interrupt)1	`renesas,rx-swint`
Serial controller	on-chip	Renesas RX SCI UART controller1 3	`renesas,rx-uart-sci`
SPI	on-chip	Renesas RX RSPI1	`renesas,rx-rspi`
SRAM	on-chip	Generic on-chip SRAM1	`mmio-sram`
Timer	on-chip	Renesas RX timer node1	`renesas,rx-timer-cmt-start-control`
Timer	on-chip	Renesas RX timer node1 3	`renesas,rx-timer-cmt`

Programming and Debugging

The ek_rx261 board supports the runners and associated west commands listed below.

	flash	debug	attach	debugserver	reset	rtt
jlink	✅ (default)	✅ (default)	✅	✅	✅	✅
rfp	✅

Applications for the ek_rx261 board can be built, flashed, and debugged using standard Zephyr workflows. Refer to Building an Application and Run an Application for more details.

Flashing

Program can be flashed to EK-RX261 via either the on-board E2 Emulator OB or an external SEGGER J-Link debugger (using the FINE interface).

Renesas Flash Programmer (RFP) can be used with the on-board E2 Emulator OB. RFP is available at: https://www.renesas.com/software-tool/renesas-flash-programmer-programming-gui
SEGGER J-Link can be used with the 14-pin FINE connector (J27) for external flashing. J-Link drivers are available at: https://www.segger.com/downloads/jlink/

Connect to the debugger:
- For E2 Emulator OB: connect USB DEBUG1 (J26)
- For J-Link: connect to 14-pin FINE header (J27)
Set jumper configuration according to the selected flash mode:
- E2 Emulator OB (on-board):
  - J22: Open
  - J23: Jumper on pins 2-3
  - J24: Open
  - J25: Open
- J-Link (external debugger):
  - J22: Open
  - J23: Jumper on pins 1-2 or 2-3
  - J24: Closed
  - J25: Open

Run flashing command:

west flash  # For E2 Emulator OB
west flash -r jlink     # For J-Link (external debugger)

Debugging

The EK-RX261 supports debugging through:

On-board E2 Emulator OB (via USB DEBUG1)
External debugger using the 14-pin FINE header (J27)

To use on-board E2 Emulator:

J22: Open
J23: Jumper on pins 2-3
J24: Open
J25: Open

To use external debugger:

J24: Closed
J22: Open
J23: Jumper on pins 1-2 or 2-3 (depending on desired pull-up/down)
J25: Open

Note: External debugger (e.g., E2 Lite) cannot power the board. Supply external 5V via USB or TP5/TP6.