Renesas Electronics Introduces R8C Microcontrollers with USB Host/Function and USB On-The-Go Support

Taking advantage of its proven track record for mid- to high-end MCUs with built-in USB controllers, Renesas Electronics has responded to market needs by releasing the new low-end MCUs that incorporate a USB host/function controller. In the R8C/34K Group of MCUs, the USB peripheral also can be configured for On-The-Go (OTG) functionality to provide greater flexibility and simplify system design. The new devices offer variants ranging from 32 to 128 kilobytes (KB) with up to 10KB of SRAM, and 4KB of data flash for data storage, and are offered in a 7x7 millimeter (mm) or 6×6 mm package.

Following are key features of the new USB MCUs:

(1) High-functionality USB host/function controller

The USB controller conforms to the USB 2.0 full speed (12 Mbps) specifications. Furthermore, the controller consists of five high-performance and flexible communication pipes, and each pipe includes its own FIFO memory (for a total of 448 bytes). Thus, applications can select double or single buffering and the communication direction according to the needs of the system application in software.

When this USB controller is used as a host, it can achieve highly efficient USB communication by automatically repeating transfers using the free time in the USB frame. Also, since the transfer scheduling is performed in hardware, the CPU load is reduced significantly.

When this USB controller is used as a USB function controller, it performs the state management required for USB communication and the control transfer stage management in hardware. This means that communication with a USB host can be implemented with even simpler software thereby reducing development time. Since this USB controller includes a USB power supply regulator, a single-voltage power supply (3.0 to 5.5 volts) provided by the USB cable can be utilized to minimize system cost.

The R8C/34K group products allow the USB host and USB function operations to be switched with register settings and can also support USB OTG.

(2) Support for a wide range of low-power modes

Just as the existing R8C/3x Series does, the new MCUs provide both wait mode and stop mode, which significantly reduce power consumption. Furthermore, the internal PLL circuit for the USB clock can be disabled when the USB is not required to reduce the power consumption even more.

(3) Compact package

The new R8C/34K and R8C/34U Group MCUs, and the R8C/3MK and R8C/3MU Group MCUs, come in a 7×7 mm 48-pin LQFP package and a 6×6 mm 40-pin QFN package, respectively, allowing system designers to select the best package for the application system.