STK17TA8

February 2004

19

Document Control # ML0023 rev 0.3

WDT

Watchdog timeout selection. The watchdog timer interval is selected by the 6-bit value in this register. It represents a multiplier of the 32 Hz

count (31.25 ms). The minimum range or timeout value is 31.25 ms (a setting of 1) and the maximum timeout is 2 seconds (setting of 3Fh).

Setting the watchdog timer register to 0 disables the timer. These bits can be written only if the WDW bit was cleared to 0 on a previous

cycle.

1FFF6h

Interrupt Status/Control

D7

D6

D5

D4

D3

D2

D1

D0

WIE

AIE

PFE

ABE

H/L

P/L

XX

WIE

Watchdog Interrupt Enable. When set to 1 and a watchdog timeout occurs, the watchdog timer drives the INT pin as well as the WDF flag.

When set to 0, the watchdog timeout affects only the WDF flag.

AIE

Alarm Interrup Enable. When set to 1, the alarm match drives the INT pin as well as the AF flag. When set to 0, the alarm match only

affects the AF flag.

PFE

Power-Fail Enable. When set to 1, the alarm match drives the INT pin as well as the AF flag. When set to 0, the power-fail monitor affects

only the PF flag.

ABE

Alarm Battery-backup Enable. When set to 1, the alarm interrupt (as controlled by AIE) will function even in battery backup mode. When

set to 0, the alarm will occur only when Vcc>Vswitch.

H/L

High/Low. When set to a 1, the INT pin is driven active high. When set to 0, the INT pin is open drain, active low.

P/L

Pulse/Level. When set to a 1, the INT pin is driven active (determined by H/L) by an interrupt source for approximately 200 ms. When set

to a 0, the INT pin is driven to an active level (as set by H/L) until the Flags/Control register is read.

1FFF5h

Alarm - Day

D7

D6

D5

D4

D3

D2

D1

D0

M

0

10s alarm date

alarm date

Contains the alarm value for the date of the month and the mask bit to select or deselect the date value.

M

Match. Setting this bit to 0 causes the date value to be used in the alarm match. Setting this bit to 1 causes the match circuit to ignore the

date value.

1FFF4h

Alarm - Hours

D7

D6

D5

D4

D3

D2

D1

D0

M

0

10s alarm hours

alarm hours

Contains the alarm value for the hours and the mask bit to select or deselect the hours value.

M

Match. Setting this bit to 0 causes the hours value to be used in the alarm match. Setting this bit to 1 causes the match circuit to ignore the

hours value.

1FFF3h

Alarm - Minutes

D7

D6

D5

D4

D3

D2

D1

D0

M

10s alarm minutes

alarm minutes

Contains the alarm value for the minutes and the mask bit to select or deselect the minutes value

M

Match. Setting this bit to 0 causes the minutes value to be used in the alarm match. Setting this bit to 1 causes the match circuit to ignore

the minutes value.

1FFF2h

Alarm - Seconds

D7

D6

D5

D4

D3

D2

D1

D0

M

10s alarm seconds

alarm seconds

Contains the alarm value for the seconds and the mask bit to select or deselect the seconds value

1FFF7h

Watchdog Timer

D7

D6

D5

D4

D3

D2

D1

D0