MB91480 Series 32-bit Microcontrollers for White Goods

China's home appliances experienced a sales peak in the 1980s or early 1990s. After about 10 years of use, these home appliances have approached or exceeded their design lifespan, indicating that China's home appliances are entering a peak period of replacement. As a major producer and consumer of home appliances, the current social ownership of refrigerators has reached 120 million units, washing machines 170 million units, televisions 400 million units, and computers 16 million units. Faced with such a huge competitive market, home appliance companies are increasingly promoting high-performance, low-power and variable-frequency white appliances in order to win the favor of consumers. 

Overview 

Fujitsu has added the MB91480 series for high-performance white appliances to its 32-bit microcontroller "FR Family" product lineup. This series is specially designed and developed for white appliances that have become increasingly multifunctional and high-performance in recent years. The MB91480 series achieves energy saving, low noise and environmental protection functions through ultra-precise control. 

In recent years, white goods have become more and more diverse with various sensor information, such as multi-sensing temperature control functions and steam cooking functions used in microwave ovens, and air pollution management functions and air humidity increase functions used in air conditioners. In addition, people are constantly pursuing microwave ovens and induction cookers (IH cookers) with more precise temperature control functions, and air conditioners and washing machines with lower noise. In order to make these a reality, it is necessary to process the information obtained from various sensors in real time and perform ultra-precise control. 

The MB91480 series is a high-performance microcontroller for home appliances with a 5V interface, based on our company's original RISC CPU structure. In order to meet the requirements for high-functionality of white goods such as air conditioners, washing and drying machines, refrigerators, IH cooking stoves, and microwave ovens, this product is equipped with a 32-bit CPU core with a maximum processing speed of 80MHz, a high-performance A/D converter, and a 32-bit high-speed product and sum dedicated calculation macro. It is also equipped with two units of multi-function timers that can perform three-phase PWM control and can control two motors. 

Product lineup 



Figure 1 shows our inverter product lineup of 32-bit microcontrollers with a 5V interface. 

So far, Fujitsu has developed and produced the MB91260, MB91265 and MB90470 series products. The MB90470 series products have greatly improved CPU processing capabilities and enhanced A/D converter functions. This time, the MB91480 series has been added to the product lineup. This series is based on the MB91470 series and is equipped with two multi-function timer units that can perform three-phase PWM control and can control two motors. In addition to the MB91F487 equipped with flash memory, this product is also planning to develop a MASK ROM version. 

Features of the MB91F487 

FR60 core is used 

. FR60 is a 32-bit RISC CPU core produced by our company that uses a core compatible with the FR series instructions. This core has the characteristics of high performance and low power consumption, and the maximum operating frequency can reach 80MHz (vibration source: 10MHz, PLL: 8 times). 

Equipped with a high-speed A/D converter 

Equipped with an 18-channel 8/10-bit resolution A/D converter. It can also fully meet the use of frequently measuring analog values. The minimum conversion time of the A/D converter is only 1.2μs. This product is equipped with three A/D converter units (4 channels × 2 units / 10 channels × 1 unit). Therefore, the converter units can be used according to the various measurement purposes. [page]



Image 1 Appearance 

Linkage function of A/D converter 

All A/D converter units can be linked to the free timer (output comparison function) of the multi-function timer to start. And the DMA conversion data can be sent with the end of the A/D converter conversion as a trigger. In this way, the current flowing to the protection resistor of the motor drive element can be detected by the A/D converter, and the inverter control such as the position control of the rotating element can be effectively performed. 

In the linkage with the free timer (output comparison function), not only can it be started by COMPARE CLEAR coincidence and zero detection point, but it can also be started by delay from this point, and the A/D start point can be adjusted. 

Equipped with high-speed product-sum calculation macros 

and combined with product-sum calculation processing hard macros, the calculation speed of the microcontroller is further accelerated. 32-bit × 32-bit + 72-bit product-sum calculation is performed in 7 cycles (maximum 80MHz), and the calculation is performed in pipeline processing. Therefore, just like the row and column calculation in the 180-degree sine wave power-on method inverter control, the effect is more obvious if a large number of calculations are performed at one time. In addition, since it can work simultaneously with the CPU's calculation processing, the CPU can perform other processing during the macro calculation. 

Supports UART/SIO/I2C 

Equipped with serial interface 

The serial interface of this product can switch one serial interface unit to UART, SIO, and I2C by mode setting. MB91F487 is equipped with 3 channels of this unit. It supports interface IC control realized by I2C interface, SPI-ROM connection realized by SIO interface, synchronous serial communication with other microcontrollers, and communication with other boards through UART interface. 

Equipped with BASE TIMER 

BASE TIMER can be selected from 16-bit PWM timer, 16-bit PPG timer, 16/32-bit Reload timer, and 16/32-bit PWC timer by mode setting. In addition, by combining even channels and odd channels, BASE TIMER can be used in 32-bit mode. MB91F487 is equipped with 4 base timers. One timer can be used for different purposes by mode switching, so it can flexibly respond to customer application needs. 

It is equipped with 2 multi-function timer units 

. The multi-function timer consists of the following functions. 

• 16-bit up/down counter × 3
• 16-bit output compare × 6
• 16-bit input capture × 4
• 8/16-bit PPG timer × 3
• Waveform generator × 1
• A/D start comparison × 3

It can generate the carrier waveform required for inverter control, generate basic signals, generate NON OVER LAP signals, and control various signals (waveform generator). It can also generate A/D converter start signals synchronized with the timer used to control the inverter, measure input pulse width, etc. 

It is equipped with three 16-bit up and down counters, and the counter used for output comparison can be arbitrarily selected. It can not only be used for synchronous use of 6 channels of three-phase motor frequency conversion control, but also can perform separate PWM control through each two channels, which can be used for multiple single-phase motor control and multiple IH cooking stove control. 

The pulse waveform of the PPG timer can be superimposed on the output waveform, so the frequency conversion control of the 120" 150-degree sine wave power-on method can be realized with the CPU burden and development workload equivalent to the 120-degree sine wave power-on method. In this way, even without using the 180-degree sine wave power-on method with a large development workload and CPU burden, power control in frequency conversion control can be realized more smoothly. 

This product is equipped with two multi-function timer units with this function, which can easily realize the control of two motors with one chip. 



Figure 2 illustrates that the frequency conversion control varies depending on the power-on method. 



Table 1 is the specifications of MB91F487. [page]


Figure 3 is a block diagram of MB91F479. 

Application Examples 

Figure 4 shows an application example of MB91F487. MB91F487 can be used as a main control microcontroller for air-conditioning outdoor units that control compressors and fan motors. 


Figure 4 MB91F487 application examples