Combining Vector Control and User Interface/Machine Functions into a Single Microcontroller for White Goods Applications

In many white goods applications, high-performance vector speed control is implemented in a standalone microcontroller (MCU) while user-interface and machine-control functions are implemented in a second microcontroller. This paper introduces SuperH RISC 32-bit microcontrollers from Renesas Technology that are specifically designed to combine all functions into one MCU, thereby reducing system cost and achieving product-development advantages. We begin by defining the requirements for a single-MCU system in terms of MIPS, flash/SRAM size, peripherals and pin count. Then we compare this system to a multiple-MCU solution and discuss the advantages of the single-MCU approach, such as one based on a SuperH device. An optional on-chip floating point unit (FPU) is used to increase computing speed, and an integrated set of peripherals (motor timer unit, DMA ADC and interrupt controller) reduces CPU bandwidth usage for sophisticated speed control using a vector formulation. This system gives a product engineering team additional design flexibility. A specific case is analyzed in terms of CPU bandwidth usage to illustrate these advantages.