User's Guide

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Timer Registers

5.6 Watchdog Timer Control Register (WDTCR)

The watchdog timer control register (WDTCR) is shown in Figure 20 and described in Table 14. This

Figure 20. Watchdog Timer Control Register (WDTCR)

31 16

WDKEY

R/W-0

15 14 13 12 11 0

WDFLAG WDEN WDKEY Reserved

R/W-0 R/W-0 R/W-0 R/W-0

LEGEND: R/W = Read/Write; -n = value after reset

Table 14. Watchdog Timer Control Register (WDTCR) Field Descriptions

Bit Field Value Description

31-16 WDKEY 0000h - Watchdog timer service key bits. Before a watchdog timeout event occurs, only a write

FFFFh sequence of a A5C6h followed by a DA7Eh services the watchdog timer. Any other write

triggers a watchdog timeout event immediately. The default value of WDKEY is 0000h.

WDKEY is not applicable in the general-purpose timer mode.

15 WDFLAG Watchdog timer flag bit. WDFLAG is cleared when the watchdog timer is moved to the active

state, when a hardware reset occurs, and when 1 is written to WDFLAG.

0 No watchdog timer timeout event occurred.

1 Watchdog timer timeout event occurred.

14 WDEN Watchdog timer enable bit. WDEN must be set to move the watchdog timer to the pre-active

state (see Figure 12).

0 Watchdog timer is disabled. Watchdog timer output pin is disconnected from the watchdog

timer timeout event, and the timer counter starts to count. The timer is in the general-purpose

timer mode.

1 Watchdog timer is enabled. The watchdog timer output pin is connected to the watchdog

timeout event. The watchdog timer can be disabled by a watchdog timeout event or by a

hardware reset.

13-12 WDKEY 00b - 11b Watchdog idle enable key bits. A write sequence of 01b followed by 10b is required before the

watchdog timer can enter the idle mode. Writing 00b to WDKEY prevents the watchdog timer

from entering the idle mode. WDKEY is not applicable in the general-purpose timer mode.

11-0 Reserved 0 Reserved. The reserved bit location is always read as 0. A value written to this field has no

effect.

SPRU818B–December 2005–Revised September 2010 C6472/TCI648x 64-Bit Timer

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