R5F21104FP#U0 - 16-bit 16MHz R8C MCU | Renesas
MPN: R5F21104FP#U0 ✗ End of LifeR5F21104FP#U0 Overview
A microcontroller is a semiconductor containing a processor core, program memory, data memory, peripheral interfaces, and dedicated I/O in one integrated circuit. The R8C architecture places this device in the hierarchy of embedded microcontrollers, embedded processors, programmable controllers, and semiconductors. Compared with a discrete processor design, an integrated MCU reduces board area and simplifies the relationship among firmware execution, pin multiplexing, timing, and serial communications.
The verified data identifies a 16-bit R8C core operating at up to 16 MHz, with 16 KB of flash organized as 16K x 8. The device is available in a 32-LQFP package measuring 7 x 7 mm and is associated with a 3 V to 5 V operating class. The #U0 ordering suffix and tray packaging are reflected in distributor records, while another distributor description identifies the part as lead-free.
The R8C/1x/10 family combines a compact general-purpose microcontroller architecture with embedded flash and dedicated peripheral resources. Its 16 MHz clock rate provides a clear baseline for control-loop, monitoring, human-interface, and communication-management tasks. Flash memory retains application firmware in the device itself, while the 32-LQFP package provides 32 external leads for power, ground, reset, clock, serial interfaces, timers, and general-purpose I/O according to the manufacturer datasheet.
Typical uses include industrial controllers, sensor-interface equipment, compact appliance controls, building-control modules, and communication-oriented embedded equipment. A design using this MCU can consolidate a small state machine, periodic sensor sampling, actuator commands, and local diagnostics into one component. For battery- or USB-powered products, the 3 V to 5 V class is especially useful, although the final power budget must be checked against the exact operating conditions.
Designers should preserve the decoupling and signal-integrity layout shown in the manufacturer datasheet, provide a stable clock and reset arrangement, and confirm that every peripheral function assigned to a multiplexed pin remains available in the selected package. Firmware should also be validated against the operating temperature range and supply limits before production release.
This page consolidates the verified distributor and manufacturer information, distinguishes a documented same-family upgrade from unsupported substitutes, and adds practical selection and design guidance that can be applied without confusing functional alternatives with true pin-compatible drop-in replacements.
Drop-in alternatives for R5F21104FP#U0 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with R5F21104FP#U0 (same form factor and footprint) — differing in Lead-Free Status, Operating Temperature Range, Package, RAM Size.
R5F21105FP#U0
✅ Drop-In📋 Reference alternative (not in catalog)
R5F21114FP#U0
✅ Drop-InContact for price
View Datasheet →R5F21104FP#U0 Maximum Ratings & Electrical Characteristics
| Microcontroller Type | 16-bit R8C microcontroller |
| Series | R8C/1x/10 |
| Maximum CPU Frequency | 16 MHz |
| Flash Memory Size | 16 KB |
| Flash Organization | 16K x 8 |
| RAM Size | 1 KB |
| Operating Voltage Range | 2.7 V to 5.5 V |
| Nominal Supply Class | 3 V to 5 V |
| Package | 32-LQFP, 7 x 7 mm |
| Pin Count | 32 pins |
| Mounting Type | Surface mount |
| Operating Temperature Range | -20 °C to +85 °C |
| Lead-Free Status | Lead-free |
| RoHS Status | Compliant |
| AEC-Q100 Qualification | Not applicable |
R5F21104FP#U0 32-lqfp, 7 x 7 mm Pin Configuration Guide
Pin configuration for R5F21104FP#U0 (32-lqfp, 7 x 7 mm package). This digital IC includes GPIO, communication interfaces (UART, SPI, I2C), and power pins. Refer to the manufacturer datasheet for alternate pin functions and configuration options. Essential for embedded system design and PCB layout.
No detailed pinout data available for R5F21104FP#U0.
Refer to the datasheet for full pin configuration.
Typical Applications
R5F21104FP#U0 is suitable for 6 applications: Industrial Sensor Interface, Building Automation Controller, Compact Appliance Controller, Portable Measurement Module, Communication Equipment Control, LED and Display Sequencer.
Industrial Sensor Interface
The R5F21104FP#U0 fits compact sensor-interface modules that periodically acquire measurements, apply filtering, and report results over a serial link. Its 16-bit R8C core operates at up to 16 MHz, providing ample baseline performance for small state machines and fixed-point signal processing. The verified 16 KB flash capacity holds embedded configuration and application firmware, while 1 KB of RAM supports sample buffers and control variables. Operating from a 2.7 V to 5.5 V range permits integration with both 3.3 V and 5 V peripherals. The 32-LQFP 7 x 7 mm package also preserves a compact board footprint. Before finalizing the design, verify the required UART, timer, ADC, and I/O assignments against the manufacturer pin table and confirm that firmware growth will not exceed the available 16 KB flash region.
Recommended
Building Automation Controller
The R5F21104FP#U0 can serve as the local controller in a building-automation node responsible for monitoring inputs and issuing actuator commands. Its 16 MHz R8C core is suitable for scheduled sampling, debounce logic, alarm thresholds, and communication packet handling, while 16 KB of embedded flash permits firmware to remain self-contained. The 1 KB RAM capacity is adequate for compact working sets but requires disciplined allocation if large buffers are introduced. Its -20 °C to +85 °C range supports many indoor and enclosure-based deployments, and the 2.7 V to 5.5 V operating range simplifies integration with common low-voltage equipment. Designers should verify communication-interface availability, watch-dog behavior, and pin multiplexing in the datasheet before selecting this MCU for a specific building-control protocol.
Recommended
Compact Appliance Controller
The R5F21104FP#U0 is appropriate for compact appliance-control boards that coordinate user inputs, sensors, relays, indicators, and a low-speed communication interface. At 16 MHz, its 16-bit R8C core can execute deterministic control logic and multi-stage debounce routines without relying on an external processor. The 16 KB flash provides room for a focused application program, while 1 KB RAM can hold control state and short communication buffers. Its 32-LQFP 7 x 7 mm package reduces board area compared with larger leaded packages and supports automated assembly. The verified 2.7 V to 5.5 V supply range aligns with many appliance control boards, although motor, heater, and mains-connected subsystems require separate isolation and safety circuitry. Firmware developers should confirm timer, PWM, and serial-pin availability for the exact board configuration.
Recommended
Portable Measurement Module
The R5F21104FP#U0 can support portable measurement modules that combine sensor conditioning, digital filtering, local status indication, and data transfer. Its low-voltage operation from 2.7 V to 5.5 V is useful for battery- and USB-powered designs, while the 16 MHz clock provides enough execution time for routine calculations and protocol framing. The 16 KB flash stores application firmware and calibration tables, and the 1 KB RAM can hold short acquisition windows. Because the MCU includes limited memory, sensor data should generally be streamed or summarized rather than retained in large on-device buffers. The 32-LQFP package is compact but requires careful exposed-pad and soldering-process control. Engineers should evaluate standby current, analog peripheral availability, and the permitted temperature range from the manufacturer datasheet before finalizing a battery-powered design.
Recommended
Communication Equipment Control
The R5F21104FP#U0 fits communication-equipment modules where a small controller supervises reset, status LEDs, configuration registers, and a host or peripheral serial interface. Its 16-bit R8C core and 16 MHz operating frequency support packet framing, timeout handling, and supervisory logic, while the 16 KB flash can retain configuration parameters and firmware. The 1 KB RAM requirement calls for careful buffer sizing if continuous data transfer is involved, so high-throughput designs should avoid routing bulk payloads through the MCU. The 32-LQFP 7 x 7 mm package is useful in space-constrained line cards and gateways, and the 2.7 V to 5.5 V range supports mixed-voltage boards when interface levels are handled separately. Firmware and hardware engineers must confirm UART or other communication pins, peripheral variants, and reset behavior against the selected ordering code.
Recommended
LED and Display Sequencer
The R5F21104FP#U0 can control status LEDs, small displays, and sequenced indicators in consumer or industrial products. The 16 MHz R8C core can refresh multiplexed indicators, manage button input, and coordinate lighting effects with minimal external logic. Its 16 KB flash stores the display and animation routines, while 1 KB RAM is suitable for short frame buffers and state tracking. The 32-LQFP 7 x 7 mm package supports compact control boards, and the 2.7 V to 5.5 V operating range accommodates common display-driver voltages. A production design should account for LED current limits, driver-interface timing, and the available timer or serial outputs rather than assuming a dedicated LED-driver function. Pin multiplexing and electrical limits must be confirmed from the manufacturer datasheet for the exact package variant.
Recommended
Recommended Products Summary
Engineering reference data for R5F21104FP#U0 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | R5F21105FP#U0 | R5F21114FP#U0 |
|---|---|---|---|
| Brand | Renesas Electronics | Renesas Electronics | Renesas Electronics |
| Package | 32-LQFP (7x7) | 32-LQFP (7x7) - same | 32-LQFP (7x7) - same |
| CPU Architecture | 16-bit R8C | 16-bit R8C | 16-bit R5F211 family |
| Flash Memory | 16 KB | 32 KB, 100% increase | 16 KB |
Key Differentiators
- Lower verified unit price with sufficient memory for compact control programs (vs R5F21105FP#U0)
- Documented same-package memory-expansion path (vs R5F21105FP#U0)
- Compact 16-bit control platform with a documented 16 MHz operating point (vs R5F21114FP#U0)
Design Notes
Design the supply rail for the full verified 2.7 V to 5.5 V operating range and place the manufacturer-recommended input and output capacitors close to their corresponding pins. Keep sensitive return currents away from digital switching paths, and provide local bulk capacitance where a long supply trace or source impedance could prevent the input voltage from settling during startup. The verified data does not identify the required capacitor values or ESR, so those values must be taken from the manufacturer datasheet rather than estimated.
Preserve the manufacturer layout for the 32-LQFP footprint, including the thermal-via pattern where specified. A 7 x 7 mm package offers limited escape-routing space, so assign pins according to the verified peripheral functions before routing power and communication signals. Keep the oscillator loop short and symmetrical, provide a clean return beneath the device, and avoid routing fast or switching nets between the MCU and its decoupling capacitors.
Do not treat every 32-LQFP R5F211-family device as an automatic drop-in replacement. The verified upgrade data specifically identifies R5F21105FP#U0 as the same-package memory-expansion option, while the supplied R5F21114FP#U0 comparison does not establish every peripheral and pin assignment. Before substitution, compare the manufacturer package diagrams, power pins, oscillator connections, reset behavior, peripheral multiplexing, and programming interface. Firmware should also be rebuilt and regression-tested for the exact alternate orderable code.
Plan the firmware footprint before committing to the 16 KB flash and 1 KB RAM limits. Reserve space for a bootloader, configuration data, calibration tables, and future updates rather than filling the flash to its theoretical capacity. Use compile-time linker checks and map-file review to identify code growth, and keep stack-heavy routines out of interrupt handlers. The R5F21105FP#U0 is the documented same-package option when the existing memory budget is insufficient.
Compliance Information
LCSC identifies the part as RoHS-compliant, and Mouser identifies it as lead-free. No explicit REACH, halogen-free, conflict-minerals, or automotive-qualification declaration was present in the verified data.
