10 / 20 page
FM3204/16/64/256
Rev 2.1
Dec. 2004
Page 10 of 20
09h
Watchdog Restart & Flags
D7
D6
D5
D4
D3
D2
D1
D0
WTR
POR
LB
-
WR3
WR2
WR1
WR0
WTR
Watchdog Timer Reset Flag: When the /RST signal is activated by the watchdog the WTR bit will be set to 1. It
must be cleared by the user. Note that both WTR and POR could be set if both reset sources have occurred since
the flags were cleared by the user. Battery-backed. Read/Write (internally set, user can clear bit).
POR
Power-on Reset Flag: When the /RST pin is activated by either VDD < VTP or a manual reset, the POR bit will be
set to 1. It must be cleared by the user. Note that both WTR and POR could be set if both reset sources have
occurred since the flags were cleared by the user. Battery-backed. Read/Write (internally set, user can clear bit).
LB
Low Backup Flag: On power up, if the VBAK source is below the minimum voltage to operate the event counters,
this bit will be set to 1. The user should clear it to 0 when initializing the system. Battery-backed. Read/Write
(internally set, user can clear bit).
WR3-0
Watchdog Restart: Writing a pattern 1010b to WR3-0 restarts the watchdog timer. The upper nibble contents do
not affect this operation. Writing any pattern other than 1010b to WR3-0 has no effect on the timer. This allows
users to clear the WTR, POR, and LB flags without affecting the watchdog timer. Write-only.
00-08h
Reserved – DO NOT USE THIS ADDRESS SPACE
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