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Microcontroller incorporating a 24-bit ΔΣ A/D converter for measuring instruments including smart meters


MCUs in the RX21A group will have advanced analog and security features such as a 24-bit Delta Sigma ADC, MPU (Memory Protection Unit), AES encryption engine (256 bit key length), temperature sensor and a real real-time clock calendar (RTCC) with auto calibration function, alarm function with up to 3 tamper inputs and a binary count mode. Zero wait states on board Flash will range from 256KB to 512KB.


Applications that will benefit from the RX21A Group includes: single-phase smart meters, three-phase smart meters, medical and industrial.

Key Features:

CPU core RX CPU General registers: 32-bit x 16
Multiplier: 32-bit multiplier Divider: Yes
Multiply-accumulator: Yes (two types: memory-to-memory operations and register-to-register operations)
Memory-protection unit (MPU)
Maximum operating frequency 50 MHz
Power supply voltage 1.8 to 3.6 V
Program Flash max. 512 KB
Data Flash 8 KB
SRAM max. 64 KB
On-chip peripheral functions Transfer functions DMA controller (DMACA): 4 channels
Data transfer controller (DTCa)
Timers Multi-function timer pulse unit 2: 16 bits x 6 channels (MTU2a)
Port output enable 2 (POE2a)
8-bit timer (TMR): 8 bits x 2 channels x 2 units
Compare match timer (CMT): 16 bits x 2 channels x 2 units
Watchdog timer (WDTA): 14 bits
Realtime clock (RTCb)
Communication functions Serial communications interface (SCIc): 5 channels (1ch: IrDA x 1channel)
I2C bus interface (RIIC): 100, 80-pin:2 channels; 64-pin: 1 channel
Serial peripheral interface (RSPI): 2 channels
Analog functions 24-bit Delta-sigma A/D converter (DSAD): 100-pin: 7 channels; 80-pin: 4 channels; 64-pin: 3 channels
10-bit A/D converter (AD): 100, 80-pin: 7 channels; 64-pin: 4 channels
10-bit D/A converter (DA): 100, 80-pin: 2 channels; 64-pin: none
ComparatorA (CMPA): 100, 80-pin: 2 channels;, 64-pin: 1 channel
ComparatorB (CMPB): 2 channels
Encryption functions Data Encryption Unit (DEU)
Safety functions Clock Frequency Accuracy Measurement Circuit (CAC)
Data Operation Circuit (DOC)
Independent watchdog timer (IWDTa): 14 bits
Self-diagnosis Function of 10-bit ADC/AD Input Disconnection
Detection CRC Calculator (CRC)
Clock Generation Circuit Main clock oscillator
Sub-clock oscillator
Low-speed on-chip oscillator (LOCO)
High-speed on-chip oscillator (HOCO)
PLL frequency synthesizer
Dedicated on-chip oscillator for the IWDT
Others Event link controller (ELC)
Multifunction Pin Controller (MPC)
Temperature Sensor (TEMPSa)

Power-on reset Circuit (POR)

Voltage Detection Circuit (LVD)
On-chip debugging function Planning
Low power consumption modes 4 modes
Sleep mode
All-module clock stop mode
Software standby mode
Deep software standby mode
Packages PLQP0064KB-A (64-pin LFQFP,10x10mm,0.5mm pitch)
PLQP0080KB-A (80-pin LFQFP,12x12mm,0.5mm pitch)
PLQP0100KB-A (100-pin LFQFP,14x14mm,0.5mm pitch)
PTLG0100JA-A(100-pin TFLGA,7x7mm,0.65mm pitch)


Pin Count / Memory Size Lineup:

Program Flash


Block Diagram:

RX21A Block Diagram

Below you will find information to support the development of your application.
You can find an explanation of orderable part numbers here.

Resources for Software and Hardware

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FAQ Frequently asked questions and useful hints for development.
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Video Watch videos related to this product.


Software Design Support

Title Description
CS+ An integrated development environment that can be used for coding, assembling/compiling, and simulation. (Also included with Renesas Starter Kits.)
e2 studio Renesas eclipse embedded studio, known as e² studio, is a complete development and debug environment based on the popular Eclipse CDT project.
E1 A standard Renesas on-chip debugging emulator that enables users to carry out ample debugging for real development at low cost. (Also included with starter kits.)


Hardware Design Support

Title Description
IBIS/BSDL IBIS standard simulation data is required for high-speed board design and can be used to run simulations to examine and troubleshoot issues such as waveform reflection, ringing, and so on, before producing the actual board.

BSDL is a data input format supported by most IEEE 1149.1 (JTAG)-compliant tools. The automatic test pattern generation (ATPG) and automatic test equipment functions of these tools facilitate testing.
Resonator Information

Please search for your resonator on its manufacturer's site linked below. If you require optimal oscillation circuit constants for your particular system, please ask the manufacturer of the oscillator.


For Main clock resonator :

KYOCERA: Click here for RX21A oscillation evaluation result.

Murata Manufacturing: For IC Manufacturer, select Renesas Electronics, and enter R5F521A into the IC Part Number search box.


For Sub clock resonator :

KYOCERA: Click here for RX21A oscillation evaluation result.

Usando os filtros abaixo você pode filtrar os programas exemplo e as notas de aplicação que são mostradas.

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