MCUs have USB host/function and USB On-The-Go support - Embedded.com

MCUs have USB host/function and USB On-The-Go support

Renesas Electronics' first low-end flash microcontrollers (MCUs) with a built-in Universal Serial Bus 2.0 (USB) host/function controller are designed for consumer electronics, such as PC peripherals, mobile devices and healthcare equipment.

The MCUs are part of the R8C Family, and include the R8C/34K and R8C/3MK Groups, which incorporate a USB host/function controller, and the R8C/34U and R8C/3MU Groups with a USB function-only 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 devices offer variants ranging from 32 to 128 kilobytes¬† with up to 10KB of SRAM, and 4KB of data flash for data storage, and are offered in a 7×7 mm or 6√ó6 mm package.

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). 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.

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

Mass production is scheduled to begin in March 2011 and is expected to reach a combined volume of 500,000 units per month by March 2012.

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