MICROCONTROLLER SOLUTIONS

As Fast as it Gets

With its new SH708xF products, Renesas Technology again demonstrates its leading position in the area of MCUs with on-chip Flash memory. Featuring 256K or 512K of on-chip Flash, the new SH RISC microcontrollers are based on the latest MONOS Flash generation, combining maximum speed and low cost. The CPU can fetch instructions from Flash memory with an access time of 12.5nsec - faster than any other embedded Flash technology currently available. SH708xF microcontrollers are ideally suited to motor control and other industrial real-time applications.

The flagship of the new SH708xF series is the SH7086F, offering 512K of Flash memory, a rich set of peripherals and a power consumption of less than 0.5W. The SH7086F also boasts perfect real-time behaviour with guaranteed response times and fully deterministic run-time behaviour.

Specifications

The SH7086F is based on Renesas’ original SuperH architecture including a 32-bit RISC CPU core with 16 32-bit general-purpose registers, a 5-stage pipeline and 32x32-bit multiplier hardware. The instruction set is targeted towards C programming. The use of 16-bit opcodes results in reduced code size, better memory utilisation and cost reduction. At a specific performance of 1.3 Dhrystone MIPS per Megahertz, the CPU yields a processing power of more than 100 Dhrystone MIPS at a clock frequency of 80MHz.



Data transfer operations are supported by two peripheral modules to fully utilise CPU processing power. A 4-channel DMAC (Direct Memory Access Controller) supporting the entire 4-Gbyte addressing space can execute byte, word, long word and 4x long word transfers in a cycle-steal or burst mode. The additional Data Transfer Controller (DTC) offers further flexibility for memory and peripheral support.

For systems requiring large memory, the SH708xF includes an external bus interface for SRAM, Flash, SDRAM and PCMCIA with a choice of multiplexed or non-multiplexed bus, 8/16/32-bit bus width and a programmable number of wait states. Two high-performance timers (MTU2 and MTU2S) offer flexible application options and feature special operating modes for three-phase motor control applications. Each timer can control a three-phase motor. Thus, the SH708xF is suitable for applications requiring precise, high-performance controls for two three-phase motors in a single chip.

As motor control applications are characterised by tight real-time requirements, the timers include a hardware-based emergency-off feature. Supported by a priority vector interrupt controller, the CPU responds to an event within eight clock cycles. The ADC can be synchronised to the timers at the hardware level, ensuring that A/D conversions are executed exactly when required.

As the SH7086F has three A/D converters, it can be used to capture signals at three different locations. Conversion time is only 2.5µsec, and a total of 16 channels is available.

Communication with the outside world is supported by three conventional serial interfaces. These are complemented by another interface with a 16-byte FIFO stage, an SPI-compatible SSU interface and an IIC interface as well as up to 134 digital I/Os.

MONOS Memory



MONOS (Metal Oxide Nitride Oxide Silicon) memory allows access times of only 12.5nsec to be achieved, even with a 0.18μm process. This will be further reduced to 10nsec in the next-generation MONOS II technology based on a 0.15µm process. Because MONOS allows the geometry of the Flash cells to be kept small and fast, MONOS Flash is ideally suited for on-chip Flash memory offering high capacity, low cost and high speed.

An additional advantage of the small cell size is that programming can be done with lower voltages, reducing the space required for the voltage pump.

What Next?

The SH708xF series is currently available in RoHS-compliant QFP packages with 100, 112, 144 and 176 pins. However, Renesas will be introducing a new, related SH microcontroller almost every month, starting with the smaller SH7146F and SH7149F, followed by the first SH2-A-based derivative offering 512K of Flash memory and a further increase in processing power. The SH2-A core is an improved superscalar version of the SH2 core, supporting clock frequencies up to 200MHz.

For further information, including the SH7080 Group Hardware Manual, please click here