PC87591L datasheet(166/437 Pages) NSC

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Embedded Controller Modules (Continued)

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Revision 1.07

4.10.3 TWD Registers

For a summary of the abbreviations used for Register Type, see “Register Abbreviations and Access” on page 34.

TWD Register Map

Timer and WATCHDOG Conﬁguration Register (TWCFG)

The TWCFG register is a byte-wide, read/write register. It defines the WATCHDOG clock input and service method and en-

ables TWD control register locking. Setting the required configuration and locking the TWCFG stops the software from in-

terfering with the WATCHDOG operation. On reset, non-reserved bits of TWCFG are initialized to 0.

Location: 00 FEE016

Type: R/W

Mnemonic

Type

TWCFG

Timer and WATCHDOG Conﬁguration Register

R/W

TWCP

Timer and WATCHDOG Clock Pre-Scaler Register

R/W

TWDT0

TWD Timer 0 Register

R/W

T0CSR

TWDT0 Control and Status Register

R/W

WDCNT

WATCHDOG Count Register

WDSDM

WATCHDOG Service Data Match Register

Bit

76543210

Name

Reserved

WDSDME

WDCT0I

LWDCNT

LTWDT0

LTWCP

LTWCFG

Reset

00000000

Bit

Description

LTWCFG.

0: Enables read/write from/to TWCFG register

1: Any data written to it is ignored and reading from it returns unpredictable values

Once LTWCFG is set, it can only be cleared by reset.

LTWCP.

0: Enables read/write from/to TWCP register

1: Any data written to it is ignored and reading from it returns unpredictable values

Once LTWCP is set, it can only be cleared by reset.

LTWDT0.

0: Enables read/write from/to TWDT0 and T0CSR registers

1: Registers cannot be written to and TWDT0 cannot be read. Any data written to TWDT0 or T0CSR is ignored.

Reading from TWDT0 returns unpredictable values.

Once LTWDT0 is set, it can only be cleared by reset.

LWDCNT.

0: Enables write to WDCNT register

1: Any data written to it is ignored and reading from it returns unpredictable values

Once LWDCNT is set, it can only be cleared by reset. When WDSDME bit is cleared, touch operations (i.e.,

writing to WDCNT register) may be performed when LWDCNT bit is either 0 or 1.

WDCT0I.

0: Selects T0OUT clock as the WATCHDOG clock

1: Selects T0IN as the input clock

The hardware clock source selection overrides this clock selection.

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