Devices with R32C/100 CPU core deliver about 2.2x the performance M32/80 series chips and maintain upward compatibility

The R32C/118 group of microcomputers with internal flash memory expand the top end of the Renesas' M16C family ? a popular line of CISC devices that has amassed an impressive track record in embedded control systems in global markets. The new 32-bit devices run at 48MHz and achieve approximately 2.2 times the processing performance of the chips in the M32C/80 series, with which they are upwardly compatible. Applications for the microcomputers in the R32C/118 group include industrial equipment and consumer devices such as car audio systems.

The very successful M16C family of CISC microcomputers has built a long track record in control applications in automotive systems, industrial equipment, and consumer products ? a wide span of applications. The multi-faceted product line extends from the R8C/Tiny series at the low end, to the mid-range M16C/60 series, and up to the R32C/100 series at the high end (see Figure 1). The recently introduced microcomputers in the R32C/118 group join the other products at that high end that have the high-performance 32-bit R32C/100 CISC CPU core. The new devices are successors to and upwardly compatible with the chips in the M32C/80 series.

The main features of the R32C/118 group are as follows:
? Maximum operating frequency of 48MHz
? High processing performance due to the full 32-bit design of the R32C/100 CPU core
? Faster execution of arithmetic operations due to the incorporation of a single-precision floating point unit (FPU), 32-bit arithmetic unit, and 32-bit barrel shifter
? Single-clock-cycle execution of sum-of-products operations (32-bit x 32-bit + 64-bit ? 64-bit)
? Improved instruction efficiency due to larger register sizes and a greater number of registers.

The 48MHz maximum clock speed of the chips in the R32C/118 group, plus the design features of the R32C/100 CPU core, allow the new microcomputers to deliver high processing performance. Execution speed is approximately 2.2 times better than the devices in the M32C/80 series, which run at speeds up to 32MHz (see Figure 2). Moreover, because the new devices and have an upwardly compatible instruction set and can run existing M32C/80 software, engineers can improve system performance just by upgrading from an M32C/80 chip to an R32C/118 microcomputer.

Also, whereas the chips in the M32C/80 series have an operating voltage of 4.2V to 5.5V at 32MHz, those in the R32C/118 group offer a wider voltage range. They can operate at 48MHz from 3.0V to 5.5V, making them easier to use.

The microcomputers in the R32C/118 group inherit the peripheral functions of the devices in the M32C/80 series. One of those inherited peripheral functions, a two-channel CAN module with 32-slot message buffer, implements reliable communications between networked embedded systems that operate in noisy environments. With their built-in CAN module and FPU, the devices in the R32C/118 group can be used to build factory automation equipment that must perform all aspects of operations in real time, such as closed-loop process control, data logging, safety monitoring, and diagnostics.

Other on-chip peripheral functions include a 9-channel serial interface, watchdog timer, 4-channel DMA controller, advanced-functionality timers, 10-bit 26-channel A/D converter, and 8-bit 2-channel D/A converter. There is also a CRC calculation circuit for improved communication data reliability, and an X-Y converter circuit for high-speed rotations or enlargements of image data (see Figure 3).

The R32C/118 microcomputers provide 512Kbytes of on-chip flash memory and 40Kbytes of RAM for handling larger programs. They also incorporate 8Kbytes of high-endurance Data Flash that is separate from the area for storing programs and can eliminate the need for external EEPROM (Electrically Erasable and Programmable Read Only Memory).

To aid system development, the members of the R32C/118 group incorporate the New Single-wire Debugger (NSD) interface. An on-chip debugger (OCD) developed by Renesas makes it possible to connect the microcomputer to an emulator using only one pin and allows the embedded system to be debugged at full speed in the actual operating environment. The NSD can be used for on-board updating of the internal flash memory, too. A comprehensive suite of software development tools (C/C++ compiler, etc.) is also available, and an emulator for the new product group, the E30A, is under development.

The pin layout of the new devices' 14mm x 14mm LQFP package is upwardly compatible with the layout of the M32C/80 series devices, with minor exceptions. One pin is used for the previously mentioned debug interface pin, while two others are used to connect a stabilization capacitor needed due to the microcomputers' higher operating frequency.

Renesas plans to extend the R32C/118 group to meet diverse market needs with the addition of models with internal flash memory sizes between 256Kbytes and 1Mbyte and internal RAM sizes between 40Kbytes and 64Kbytes. Other planned enhancements include a 144-pin LQFP package, 5V tolerance, an internal network system controller, and more.

For more information on the R32C/118 group, click here.