The R8C/L3xM 16-bit microcontrollers have been added to the Renesas Electronics R8C/Lx series have an high-speed on-chip oscillator along with ultra-low power consumption.
The R8C/L3xM MCUs will comprise a total of four groups ranging from 52 to 100 pins with up to 128 kilobytes of programmable flash memory.
The R8C/L3xM groups include a on-chip oscillator with ±1 percent typical accuracy at room temperature and ±1.5 percent guaranteed accuracy in all temperature ranges, including aging variation after factory calibration.
The high-speed on-chip oscillator supplies the 40MHz oscillation with 1/2, 1/3, 1/4, 1/5 1/6, 1/7, 1/8 or 1/9 clock division as clock sources to the CPU and also the on-chip peripheral functions. This allows the MCU to communicate with external components via serial interfaces without any other external resonators.
The R8C/Lx MCUs have two power-down modes to provide smart power management while reducing overall system power consumption. The CPU and the real time clock (RTC) run with 32 KHz sub clock in power-off mode1, and in the power-off mode 0 only the RAM is retained which reduces the standby current consumption to almost zero. The combination of the two power-down modes offer users easy-to-access means to achieve energy efficient and smart system power management schemes.
They provide a multi-functional LCD driver for up to 4x 56 (8x 52) segments, along with large capacity on-chip Flash memory. Hardware blinking and converting functions are available. Software-selectable segment output of up to 56 pins is available and can be allocated to the segments or to I/O ports. A tuneable LCD power supply booster generates variable common voltage levels to simplify LCD design.
The four groups of MCUs are all built around the Renesas Electronics R8C CPU core, which has a proven track record in the R8C/Lx Series and delivers high performance, excellent functionality and ample flexibility. The R8C is a 16-bit CPU, but the CPU and peripheral functions are linked by an 8-bit bus. The high-speed on-chip oscillator supports a wide range of operating voltages from 1.8 to 5.5V and achieves accuracy of ± 1.0 percent at room temperature and ±1.5 percent guaranteed.
A divider circuit in a later stage is used to produce a variety of oscillation frequencies, allowing the adjustment of the serial communication interface (SCI) baud rate and the timing adjustment of the timers.
The four groups are the first LCD MCUs that are equipped with the Data Transfer Controller, which has a proven, shipped record in the H8S family and H8SX family. Easy data transfer is directly available between the register of peripheral functions and on-chip memory, without CPU operation. The Data Transfer Controller shortens the transfer operation and load of the CPU.
All the MCUs include an I2C bus interface and a synchronous serial communication unit (SSU) to enable communication with a variety of external chips. There is also an on-chip comparator function, making it possible to monitor analogue signals without the use of an A/D converter for a further reduction in power consumption. Furthermore, the integrated D/A converter provides smoother analogue output than existing pulse width modulation.
David Patterson, known for his pioneering research that led to RAID, clusters and more, is part of a team at UC Berkeley that recently made its RISC-V processor architecture an open source hardware offering. We talk with Patterson and one of his colleagues behind the effort about the opportunities they see, what new kinds of designs they hope to enable and what it means for today’s commercial processor giants such as Intel, ARM and Imagination Technologies.