General Features

• High integration: Integrates 32-bit ARM Cortex-M0, metering module, hardware temperature-compensated RTC, LCD controller and EEPROM.

• Wide voltage range: The voltage range ensuring metering accuracy is 2.8V~5.5V.

• Typical operating voltage range for CPU minimal system: 2.2V~5.5V.

• GPIO supports connection with devices of different operating voltages.

• High performance: Typical CPU operating frequency is 3.6864MHz, up to 29.4912MHz.

• Low power consumption: Typical current consumption is about 3.5mA for single-phase smart meter applications.

• Power consumption is approximately 18μA when the system runs at 32kHz.

• Overall chip power consumption is about 10μA in sleep mode.

• High precision: Active energy error less than 0.1% within 5000:1 dynamic range; typical temperature coefficient of metering reference is 5ppm.

• RTC second pulse error less than ±5ppm within -25℃ ~70℃, minimum correction resolution up to 0.068ppm.

• Package: LQFP100.

Processor

• ARM Cortex-M0 core.

• Maximum operating frequency up to 29.4912MHz; 3.6864MHz is recommended for single-phase smart meter applications.

• Supports up to 192Kbytes Flash memory; 100,000 erase/write cycles, data retention over 20 years.

• Supports up to 16Kbytes SRAM.

• Supports up to 32Kbytes EEPROM; 1,000,000 erase/write cycles, byte-level operation supported, data retention over 20 years.

• Single-cycle 32bit×32bit multiplier.

• Built-in system timer in CM0 core.

• 2 DMA controllers.

• Supports multiple wake-up methods including external interrupt.

• Complete integrated software and hardware development environment provided.

Metering Functions

• Active energy error less than 0.1% within 5000:1 dynamic range.

• Typical temperature coefficient of reference voltage is 5ppm.

• Simultaneous measurement of live/neutral dual-channel active power, reactive power, apparent power and current RMS.

• Simultaneous metering of live/neutral dual-channel active energy, reactive energy and apparent energy.

• Provides voltage RMS and voltage line frequency measurement.

• Supports gain and offset correction for sampling channels.

• Power factor measurement available.

RTC

• Automatic hardware temperature compensation, meeting national standard accuracy and power consumption requirements.

• Built-in temperature sensor: accurate temperature measurement with ±1℃ precision within -25℃～70℃.

• Power consumption lower than 2μA.

LCD Driver

• Supports 4×34, 6×32, 8×30 display modes.

• DMA automatic cyclic display without CPU intervention.

• Built-in charge pump generates LCD driving voltage for clear display over wide voltage and full temperature range.

• Automatic cyclic display power consumption lower than 20μA.

Other Peripherals

• High-speed GPIO, compatible with peripheral devices of different voltage domains.

• 10-bit ADC: time-division multiplexed for temperature sensor, battery voltage detection and general ADC use.

• LVD voltage detection: monitors chip supply voltage and external voltage.

• Two comparators CMP1 and CMP2 for external voltage detection; CMP2 consumes less than 1μA, supporting low-power power monitoring under power-off state.

• Timers: 2 × 32-bit extended timers, 2 × RTC timers, 1 × CM0 built-in system timer.

• UART: up to 5 channels, supporting auto baud rate, infrared modulation and UART wake-up.

• 2 × ISO7816 interface.

• 1 × I2C interface.

• 1 × SPI interface.

• Hardware watchdog.

• 2 key interrupts with pin multiplexing.

• 4 external interrupts with pin multiplexing.

Security & Encryption

• Hardware true random number generator compliant with NIST FIPS 140-2 standard.

• AES128/192/256 hardware encryption compliant with FIPS197; supports EBC/CBC/CTR/GCM/GMAC modes.

• ECC192 hardware accelerator.

• Refer to Renergy application notes for encryption documentation.

Card Meter Isolation

• Provides low-cost and high-reliability card meter isolation solution; refer to Renergy RN8501 card isolation specification for details.

RN821x Model Classification