The new SH-Tiny series of low-pin-count, small-package-size single-chip microcomputers use a high-performance 32-bit SH-2 CPU core. The new economical version of the SH-2 family saves space and system cost in many different embedded applications. Operating at 50MHz, they deliver the 65 MIPS throughput necessary for executing sophisticated programs in systems that achieve fast response and high accuracy. Four models in the SH7125 series launch the SH-Tiny product line: two 64-pin SH7125F models with either 128KB or 64KB of flash memory, and two 48-pin SH7124F models with the same flash memory options. The primary applications for the SH-Tiny series are motor control applications that execute high-precision control algorithms. Electric motors account for most of the power consumed by air conditioners, refrigerators, and washing machines.

Manufacturers of these and other motor-driven home appliances are striving to attain higher efficiency and energy savings, especially in light of concerns for the global environment. They also are addressing consumer preferences for products that are quiet and exhibit low levels of vibration.
Highly-precise motor-control algorithms are essential for satisfying these requirements. There is solid demand for motor-control microcomputers that offer the better processing performance obtained from higher CPU speeds. Also, inverters are now a common component of air conditioners, and they, too, require high-precision motor control. To be suitable for advanced motor controllers, microcomputers must offer enhanced peripheral functions in addition to fast CPUs.

These requirements strongly influenced the design of the Renesas SH7125 series. The four SH7125 devices are far more formidable solutions than their small size and low pin count might suggest. They have the peripheral functions needed for controlling of various types of electric motors, including brushless DC types and three-phase induction types. For example, a built-in multi-function timer-pulse unit 2 (MTU2) accommodates a sensor input and provides a three-phase PWM (pulse-width-modulation (PWM) output function. The MTU2 simplifies the generation of the PWM waveforms used to drive a three-phase motor. It has an A/D converter for motor current detection that activates automatically at a specified time, synchronized to the modulation wave. This capability reduces the processing load on the CPU core and supports single-shunt vector control of brushless DC motors.

The SH-Tiny processors also include eight 16-bit timer channels that can be used to generate a 16-pin PWM output. Among the microcomputers' many other on-chip features are two high-speed AD converter units, a serial interface, and high-speed flash memory that can be accessed in a single cycle (20ns) in all cases for maximum throughput. Operation is from a single 5V power supply. This helps keep system circuit boards simple and contributes to lower system design costs.