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3 standby control register (stcr) – FUJITSU MB91F109 FR30 User Manual

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CHAPTER 3 CLOCK GENERATOR AND CONTROLLER

3.3

Standby Control Register (STCR)

The standby control register (STCR) is used to control standby operation and specify
the oscillation stabilization wait time.

Configuration of Standby Control Register (STCR)

The configuration of standby control register (STCR) is shown below:

Bit Functions of the Standby Control Register (STCR)

[bit 07] STOP

Writing "1" to this bit puts the system in a stopped state in which the internal peripheral clock,
internal CPU clock, and oscillation are stopped.

[bit 06] SLEP

Writing "1" to this bit puts the system in sleep state in which the internal CPU clock is
stopped.

If 1 is written to both bits 7 and 6, bit 7 is given priority and therefore the system is put in a
stopped state.

[bit 05] HIZX

Putting the system in a stopped state with "1" written to this bit sets the device pins at high
impedance.

[bit 04] SRST

Writing "0" to this bit generates a software reset request.

[bit 03, 02] OSC1, 0

These bits specify the oscillation stabilization wait time. The bits and the wait time selected
by the bits have the relationships shown in Table 3.3.1. These bits are initialized by power-
on reset but are not affected by any other reset causes.

07

06

05

04

03

02

01

00

00000481

H

STOP SLEP HIZX

SRST OSC1 OSC0

000111--

R/W

Access

Initial value