MB91401

Prelminary

2004.11.12

 

 

Figure When you share the power supply for digital and for VCO

Power supply

(a)

VDD (for digital)

PLLVDD (for VCO)

APLL

PLLVSS

LSI

Logic part

VSS

Treatment of the unused pins

Leaving unused input pins open results in a malfunction, so process the pull-up or pull-down.

Treatment of OPEN pins

Be sure to use open pins in open state.

Treatment of output pins

A large current may flow to an output pin left connected to the power-supply, another output pin, or to a high capacitance load. Leaving the output pin that way for an extended period of time degrades the device. Use meticulous care in using the device not to exceed the absolute maximum rating.

About Mode (MDI2 to MDI0, VPD) pin and Test (TEST3 to TEST0) pin

Connect these pins directly to VDDE or VSS. To prevent the device from entering test mode accidentally due to noise, minimize the lengths of the patterns between individual mode pins and VDDE or VSS on the PC board as possible and connect them with as low an impedance as possible.

About power supply pins

In products with multiple VDDE, VDDI or VSS pins, the pins of the same potential are internally connected in the device to avoid abnormal operations including latch-up. However you must connect the pins to external power supply and a ground line to lower the electro-magnetic emission level to prevent abnormal operation strobe signals caused by the rise in the ground level, and to conform to the total output current rating.

The power pins should be connected to VDDE, VDDI and VSS of this device at the lowest possible impedance from the current supply source.

It is also advisable to connect a ceramic bypass capacitor of approximately 0.1 F between VDDE and VSS, and between VDDI and VSS near this device.

Crystal Oscillator Circuit

Noise near the OSCEA terminal may cause the MB91401 to malfunction.

Design the circuit board so that OSCEA terminal, OSCEB terminal and the crystal oscillator, and the bypass capacitor to ground are located as close to the device as possible.

It is strongly recommended to design the PC board artwork with the OSCEA terminal and OSCEB terminal surrounded by ground plane because stable operation can be expected with such a layout.

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Fujitsu MB91401 Treatment of the unused pins, Treatment of Open pins, Treatment of output pins, About power supply pins

MB91401 specifications

The Fujitsu MB91401 microcontroller is a versatile device designed for automotive applications, embedded systems, and industrial control. It belongs to the MB91400 series, known for its robustness and efficiency. This series integrates advanced features and technologies that cater to a wide variety of real-time applications.

One of the standout features of the MB91401 is its 32-bit RISC architecture, which operates at clock speeds up to 40 MHz. This high-performance core enables rapid processing and data handling, making it suitable for demanding applications. The microcontroller is equipped with a generous amount of Flash memory, allowing developers to store essential firmware and applications directly on the chip, enhancing reliability and reducing design complexity.

Another key characteristic is its extensive memory configuration, which includes SRAM for data storage and EEPROM for non-volatile data retention. This combination provides flexibility for developers, enabling them to tailor the memory allocation based on specific application requirements.

The MB91401 is designed with a focus on peripheral integration. It features multiple I/O ports, timer units, and A/D converters, making it an ideal choice for applications that require precise timing and analog signal processing. The analog-to-digital converters offer high resolution and fast conversion speeds, which are critical in automotive and industrial control systems where accuracy is paramount.

Safety is a critical consideration in automotive applications, and the MB91401 addresses this with built-in diagnostic features and error detection capabilities. These features help ensure that the application remains functional and safe under various operating conditions.

In terms of connectivity, the microcontroller supports various communication protocols, including CAN, UART, and SPI, facilitating seamless integration with other systems and devices. This is particularly important in automotive applications where communication between different electronic control units (ECUs) is essential for overall system functionality.

The Fujitsu MB91401 is also designed for low power consumption, making it suitable for battery-operated devices and energy-sensitive applications. Its various power-saving modes allow developers to optimize the system's performance while extending operational life.

In summary, the Fujitsu MB91401 is a powerful and flexible microcontroller that combines high-performance processing with extensive peripheral support and safety features. Its robust architecture and energy-efficient design make it an excellent choice for a wide range of automotive and industrial applications, promoting both reliability and innovation in embedded system development.