beautypg.com

Registers, 1 rsrr: reset cause register, Registers 4.1 rsrr: reset cause register – FUJITSU MB91460 SERIES FR60 User Manual

Page 157

background image

141

Chapter 9 Reset

4.Registers

4. Registers

4.1 RSRR: Reset Cause Register

Stores the cause of the previous reset, and sets the period and activation control for the watchdog timer.

• RSRR: Address 0480h (Access: Byte, Half-word)

Note: See “

Meaning of Bit Attribute Symbols (Page No.10)

” for details of the attributes.

Reading the reset request cause returns the reset cause flags and then clears the flag values to “0”.

If multiple resets occur prior to reading the register, the resulting flag values contain the bitwise OR of the flags
for each reset. That is, more than one flag may be set to “1”.

• Bit7: Initialization reset occurred flag

Indicates whether a reset (INIT) was triggered by INIT pin input.

The initialization reset occurred flag (INIT) is cleared to “0” after reading.

• Bit6: Hardware Standby reset occurred flag

Indicates whether a reset (INIT) was triggered by HST pin input.

The hardware standby reset occurred flag (HSTB) is cleared to “0” after reading.

• Bit5: Watchdog reset occurred flag

Indicates whether a reset (INIT) was triggered by the watchdog timer.

The watchdog reset occurred flag (WDOG) is cleared to “0” after reading.

• Bit4: External reset occurred flag

Indicates whether a reset (RST) was triggered by the RST pin input.

The external reset occurred flag (ERST) is cleared to “0” after reading.

• Bit3: Software reset occurred flag

7

6

5

4

3

2

1

0

bit

INIT

HSTB

WDOG

ERST

SRST

LINIT

WT1

WT0

1

0

0

0

0

0

0

0

Initial value

(INIT pin input)

-

-

-

X

X

-

0

0

Initial value

(Watchdog reset)

X

X

X

-

-

X

0

0

Initial value

(Software reset)

R/WX

R/WX

R/WX

R/WX

R/WX

R/WX

R/W

R/W

Attribute

INIT

Meaning

0

No INIT has been triggered by the INIT pin input.

1

INIT has been triggered by the INIT pin input.

HSTB

Meaning

0

No INIT has been triggered by the HST pin input.

1

INIT has been triggered by the HST pin input.

WDOG

Meaning

0

No INIT has been triggered by the watchdog timer.

1

INIT has been triggered by the watchdog timer.

ERST

Meaning

0

No RST has been triggered by the RST pin input.

1

RST has been triggered by the RST pin input.