MB91F127 Ver la hoja de datos (PDF) - Fujitsu

Número de pieza

componentes Descripción

Fabricante

MB91F127

32-Bit Microcontroller

Fujitsu 

MB91F127/F128

5. Connecting power supply terminals (VCC, VSS)

If two or more VCC, VSS terminals are used, the terminals to be placed under the same potentials are connected

with each other internally for preventing malfunctions such as latch up. However, for reducing unwanted radiation,

preventing malfunctions of strobe signals and observing total power and current ratings, be sure to connect all

of these terminals to power supply and ground externally.

Connecting power supply to VCC - VSS in impedance as low as possible is desirable.

6. Crystal oscillator circuit

Noises around X0 and X1 terminals causes malfunction of the device. Design printed wiring so that X0, X1,

and crystal oscillator (or ceramic oscillator), and bypass capacitor to the ground are aligned as close as possible

one another. Also the wiring of those elements should not cross with other wiring if possible. Printed wiring

with ground wires around X0 and X1 terminals ensures more stable operations. Such designing is strongly

recommended.

7. Treating NC terminals

Be sure to leave NC terminals open.

8. Mode terminals (MD0 through MD2)

Do not connect the mode terminals directly to VCC or VSS.

For preventing malfunctions caused by noises, make printed traces between the mode terminals and VCC or

VSS as short as possible, and connect the elements in lower impedance.

9. Turning power on

Be sure to turn on the power of the device with RST terminal placed under "L" level. Ensure a period at a

minimum of 5 cycles of internal operation clock before placing the terminal under "H" level.

10. Terminal status upon turning on power

Status upon turning on the power is indefinite. Upon turning on the power, oscillation starts and the circuit is

initialized.

11. Oscillation input upon turning on power

Upon turning on the power, be sure to input a clock signal until oscillation stabilizing wait status is released.

12. Initializing power-on reset

The device includes some built-in registers that are initialized only with power-on reset operation. For initializing

the registers, perform power-on reset by turning on the power again.

13. Recovery from Sleep/Stop status

For recovering from Sleep/Stop status initiated by a program in C-Bus RAM, reset the device instead of

recovering by an interrupt process.

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