ST92196A STMicroelectronics, ST92196A Datasheet - Page 80

• Manufacturer Part Number: ST92196A
• Description: 8/16-bit Mcu For Tv Applications With Up To 96k Rom, On-screen-display And 1 Or 2 Data Slicers
• Manufacturer: STMicroelectronics

TIMER/WATCHDOG (Cont’d)
8.1.4 WDT Interrupts
The Timer/Watchdog issues an interrupt request
at every End of Count, when this feature is ena-
bled.
A pair of control bits, IA0S (EIVR.1, Interrupt A0 se-
lection bit) and TLIS (EIVR.2, Top Level Input Se-
lection bit) allow the selection of 2 interrupt sources
(Timer/Watchdog End of Count, or External Pin)
handled in two different ways, as a Top Level Non
Maskable Interrupt (Software Reset), or as a
source for channel A0 of the external interrupt logic.
A block diagram of the interrupt logic is given in
Figure
Note: Software traps can be generated by setting
the appropriate interrupt pending bit.
Table 17
tions of interrupt/reset sources which relate to the
Timer/Watchdog.
A reset caused by the watchdog will set bit 6,
WDGRES of R242 - Page 55 (Clock Flag Regis-
ter). See
TERS.
Table 17. Interrupt Configuration
Legend:
WDG = Watchdog function
SW TRAP = Software Trap
Note: If IA0S and TLIS = 0 (enabling the Watchdog EOC as interrupt source for both Top Level and INTA0
interrupts), only the INTA0 interrupt is taken into account.
WDGEN
43.
0
0
0
0
1
1
1
1
below, shows all the possible configura-
section CLOCK CONTROL REGIS-
Control Bits
IA0S
0
0
1
1
0
0
1
1
TLIS
0
1
0
1
0
1
0
1
WDG/Ext Reset
WDG/Ext Reset
WDG/Ext Reset
WDG/Ext Reset
Ext Reset
Ext Reset
Ext Reset
Ext Reset
Reset
Enabled Sources
Figure 43. Interrupt Sources
INT0
NMI
SW TRAP
SW TRAP
Ext Pin
Ext Pin
Ext Pin
Ext Pin
INTA0
Timer
Timer
TIMER WATCHDOG
- TIMER/WATCHDOG (WDT)
0
1
0
1
MUX
MUX
Top Level
SW TRAP
SW TRAP
Ext Pin
Ext Pin
Ext Pin
Ext Pin
Timer
Timer
TLIS (EIVR.2)
IA0S (EIVR.1)
WDGEN (WCR.6)
INTERRUPT REQUEST
RESET
INTA0 REQUEST
Operating Mode
TOP LEVEL
Watchdog
Watchdog
Watchdog
Watchdog
Timer
Timer
Timer
Timer
VA00293
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