ST9 Datasheet, PDF (110/146 Pages) STMicroelectronics – USER GUIDE

ST9 USER GUIDE
4.8.2.6 WDT File
4.8.2.6.1 WDT Files for PWM Generation
The WDT function file is <wdt\appli1\wdt.c> and contains 7 functions that are initialized for
generating a simple PWM signal using the WDT (programmable duty cycle).
Port used:
– WDOUT
Table 13. WDT.C Functions
FUNCTION
void INIT_WDT(void);
void START_WDT(void);
void STOP_WDT (void);
void
Restart_Watchdog(void);
void INIT_WDT_IT(void);
void Enable_WDT_IT(void)
void
INTWDT_EndCount(void);
DESCRIPTION AND COMMENTS
WDT initialization.
It must be used before any use of the WDT.
It initializes the value loaded into the prescaler and into the counter.
To use the WDT in output mode, you must initialize the output pin in push
pull, alternate function. This means (PXC0R,PXC1R,PXC2R) = (1,1,0)
Start the Watchdog Timer.
It stops the counting of the timer (useless in watchdog mode).
This routine refreshes the Watchdog counter: At each End of Count, if this
function has not been used before, a reset is generated internally.
The periodic use of this function is the only way to avoid a reset.
This routine configure the interrupts after each End of Count using inter-
rupt channel INTA0. NMI is thus configured as the Top Level Interrupt.
Don't forget to initialize your start-up file correctly.
Enable the WDT interrupt.
Interrupt subroutine which occurs after an end of count.
The code written in the user part allow the generation of a simple PWM
signal (programmable duty cycle).
4.8.2.6.2 WDT Files in Watchdog Mode
The WDT function file is <wdt\appli2\wdt.c> and contains 4 functions that are initialized for en-
abling the WDT in Watchdog mode and refreshes it regularly.
No port is used.
Table 14. WDT.C Functions
FUNCTION
void INIT_WDT(void);
void START_WDT(void);
DESCRIPTION AND COMMENTS
WDT initialization.
It must be used before any use of the WDT.
It initializes the value loaded into the prescaler and into the counter.
Start the Watchdog Timer.
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