This week Renesas introduced the RX111, its entry-level entry into the market for ultra low power, high performance MCUs—a large market that encompasses portable medical devices, smart meters, sensors, and industrial and building automation. Operating at 109 μA/MHz (155 μA/DMIPS, 14.9 Coremarks/mA ) the RX111 family brings the RL78’s True Low PowerTM technology into the 32-bit space, adding DSP and numerous connectivity options in the process.

What we don’t have here is a failure to communicate. The RX111 supports USB 2.0 in Host, Device, and OTG modes t up to 12 Mbps; plus I2C (4 channels), SCI/UART (3 channels), SPI (4 channels), RSPI (1 channel), and up to 44 I/O ports depending on the pin count.

The RX111 is the first of the RX100 family, filling in the low end of the RX MCU line in terms of pin count and flash memory size. They’re available in a variety of packages from 36-pin SSOP (16 KB zero wait-state Flash) to a 64-pin LFQFP (128 KB Flash). The RX line now spans a wide performance range from the RX111 (32 MHz/50 DMIPS) to the RX63N (100 MHz/165 DMIPS), each with a number of low and ultra-low power modes. The RX111 family is software and tool compatible with the RX200 and RX600 lines, easing the task of creating multiple versions of the same design to meet different market requirements.

Where the RX111 really stands out is power consumption—or rather the lack of it. RX111 MCUs operate at 109 μA/MHz in Run Mode and 350 nA in Software standby from which they can wake-up in only 4.8 μs (RTC off, RAM retained). There are four software-selectable Run modes, ranging from 32 kHz to 32 MHz. The ability to dynamically switch between them can contribute greatly to reduced energy consumption.

In addition RX111s feature three Low Power Modes—Sleep, Deep Sleep, and Software Stand-By. Each peripheral can be powered off individually, with a flexible wake-up speed available through four different clock sources. All of this results in a very fine-grained, flexible power management system that puts the RX111’s power vs. performance specs almost in the RL78 range, which is about as good as it gets.

Samples of the RX111 are available now, with full production planned for September. For further information check out the RX111 Group Datasheet, the RX Family Selection Guide, and Carmelo’s video Introduction to the Renesas RX100.