104
AT94KAL Series FPSLIC
Rev. 1138G–FPSLI–11/03
Notes:
1. In overflow PWM mode, this table is only valid for OCR1X = TOP.
2. X = A or B
In up/down PWM mode, the Timer Overflow Flag1, TOV1, is set when the counter advances
from $0 000 . In overfl ow PW M mo de , the Ti m er O verflo w fla g is se t a s in norm a l
Timer/Counter mode. Timer Overflow Interrupt1 operates exactly as in normal Timer/Counter
mode, i.e., it is executed when TOV1 is set provided that Timer Overflow Interrupt1 and global
interrupts are enabled. This also applies to the Timer Output Compare1 flags and interrupts.
Watchdog Timer
The Watchdog Timer is clocked from a separate on-chip oscillator which runs at 1 MHz. This
is the typical value at V
CC
= 3.3V. See characterization data for typical values at other V
CC
lev-
els. By controlling the Watchdog Timer prescaler, the watchdog reset interval can be adjusted,
see Table 33 on page 105 for a detailed description. The WDR (watchdog reset) instruction
resets the Watchdog Timer. Eight different clock cycle periods can be selected to determine
the reset period. If the reset period expires without another watchdog reset, the FPSLIC resets
and executes from the reset vector.
To prevent unintentional disabling of the watchdog, a special turn-off sequence must be fol-
lowed when the watchdog is disabled, see Figure 58.
Figure 58.
Watchdog Timer
Table 32.
PWM Outputs OCR1X = $0000 or TOP
COM1X1
COM1X0
OCR1X
Output OC1X
1
0
$0000
L
1
0
TOP
H
1
1
$0000
H
1
1
TOP
L