Smart meters: 32bit MCU gets 24bit ADC and 512kbyte flash
Renesas has introduced 32bit microcontrollers for smart-meters.
Called the RX21A group, there are nine devices with large memories and built-in high resolution ADCs.
“The RX21A group is the first in the industry to combine a 32bit CPU, 512kbyte on-chip flash memory, and a 24bit ?? ADC,” said the firm.
Renesas already makes 8 and 16bit MCUs with on-chip 16bit ?? ADCs for meters with power calculation and ordinary billing capabilities.
“The proliferation of smart meters has created demand for MCUs that provide performance to support advanced functions such as: complex power calculation, time-of-day rate systems, diverse power services in many countries, communication data protection, and unauthorised access prevention, in addition to reduced power consumption,” said Renesas.
Also on-chip are: an encryption engine, a real-time clock (RTC), tamper detection, a temperature sensor, and IrDA.3 for infra-red comms.
ADC accuracy is 85dB SNDR (spurious-free dynamic range), claimed the firm, and the encryption engine supports 256bit key AES.
The processor, part of the RX200 series, clocks at 50MHz, and has DSP extensions for filter calculation.
Consumption is 200µA/MHz, or 1?A standby with RTC running, or 300nA when the RTC is stopped.
Product versions have three, four, or seven ADC channels, and 256, 384, or 512kbyte of flash. There is a peripheral and memory mix list here.
The firm plans a development support environment including middleware for power measurement and calibration tools.
There will also be reference designs, including one with opto-couplers to isolate the communication interface.
Samples are available now, mass production is scheduled to begin in December, and the firm expects combined volume to reach 500,000 units per month.