MB91155 datasheet(16/105 Pages) FUJITSU

16 / 105 page

MB91F155A/MB91155/MB91154

mode, the X1 pin stops when “H” is input in STOP mode. To prevent one output from competing against another,

an external resistor of about 1 k

Ω should be provided.

The following figure shows an example usage of an external clock.

Figure 2.1 An example usage of an external clock

Care During Powering Up

• When powering up

When turning on the power supply, never fail to start from setting the RST pin to “L” level. And after the power

supply voltage goes to VCC level, at least after ensuring the time for 5 machine cycle, then set to “H” level.

• Source oscillation input

At turning on the power supply, never fail to input the clock before cancellation of the oscillation stabilizing

waiting.

• Power on resetting

When powering up or when turning the power back on after the supply voltage drops below the operation

assurance range, be sure to reset the power.

• Power on sequence

Turn on the power in the order of VCC, AVCC and AVRH. The power should be disconnected in inverse order.

• Even when an AD converter is not in use, connect AVCC to the VCC level and AVSS to the VSS level.

• Even when a DA converter is not in use, connect DAVC to the VCC level and DAVS to the VSS level.

When the Clock Function (Calendar Macro) Is Not in Use

Not using the clock function, the clock oscillation pin must be configured as shown below.

MB91F155A/MB91155/MB91154

X0A

X1A

MB91F155A/MB91155/MB91154

OPEN

This product type does not allow the clock crystal oscillator to be stopped with software.

MB91155 Datasheet(PDF) 16 Page - fujitsu semiconductor