HITACHI'S SUPERH SINGLE-CHIP MICRO CONTROLLERS OFFER 65-MIPS PERFORMANCE.

Hitachi Semiconductor (America) Inc. has expanded its SuperH family of RISC processors by introducing faster, more highly integrated members of the 32-bit SH-2 series of low-cost, low-power micro controllers (MCUs): the SH7144 and SH7145 series devices at Embedded Systems Conference in San Francisco, Calif. The new single-chip MCUs operate at 3.3V, achieving relatively low power consumption at 50-MHz clock speeds. They deliver 65-million instructions per second (MIPS) performance, approximately twice that of Hitachi's current SH7044 and SH7045 chips, which they succeed. Additional and enhanced on-chip peripheral functions, 8-kilobytes (8-KB) of RAM, and 256 KB of single-supply, in-system programmable flash memory combine to help engineers improve and simplify their embedded system designs.

Applications for the SH7144 and SH7145 series RISC MCUs include consumer products such as digital video cameras, video printers, and DVD players; office automation products like printers, and color copiers; and industrial equipment, such as DC brushless motor control, heating, ventilation, air-conditioning (HVAC) systems, AC servos, inverters, machine tools and sequencers.

The need for the SH7144 and SH7145 series chips is evidenced by the fact that embedded systems are evolving away from simple control functions toward greater functionality and higher performance, including voice and image handling capability, even as system prices fall. Previously, engineers used dedicated chips or middleware executed by expensive high-performance MCUs to handle voice and image data processing. The need for lower product costs has rendered that design approach unfeasible. The SH7144 and SH7145 single-chip MCUs are well-timed solutions because they offer not only very good cost-performance, but also comprehensive peripheral functions. Now better systems can be implemented with fewer parts at lower cost.

The 256 KB of 3.3-V single-power-supply flash memory built into the SH7144 and SH7145 series chips is large enough to store not only a system control program, but also middleware for JPEG processing, speech synthesis, complex motor control and voice recognition processing. Moreover, this memory can be accessed by the 65-MIPS CPU core in one cycle for high throughput, even when system control functions are being performed.

The flash memory allows application program revisions and updates and control data rewrites when the MCU is mounted on a board. This in-system programming provides numerous advantages, such as shorter system development time, last-minute enhancements in production, and easy upgrades in the field. The flash ROM can be erased in total or by selecting individual blocks, whichever is needed.

The new MCUs are built upon the useful peripheral set provided by their predecessors. For example, the SH7144 and SH7145 devices now have a total of four serial communication interface channels, and have better connectivity to peripheral I/O modules. Also, an I(squared)C bus interface channel allows easy connections to EEPROM, audio ICs, etc. A multifunction timer pulse unit with a maximum output capability of 16 pulse width modulation (PWM) channels can be used for stepping motor control and pulse counting. It can also be used to generate a three-phase PWM output for industrial inverter control.

Although the new devices are single-chip MCUs, engineers can extend their capabilities by using the external data bus to a maximum of 32 bits. The on-chip direct memory access (DMA) controller can then be used to transfer large volumes of data at high-speeds without imposing a load on the CPU. This capability facilitates large-volume image data transfers for printers and fax machines. The 32-bit data bus extension function also allows the fast execution of programs stored in external memory.