STM8S903K3 STM8S903F3
Product overview
Activation of the watchdog timers is controlled by option bytes or by software. Once activated,
the watchdogs cannot be disabled by the user program without performing a reset.
Window watchdog timer
The window watchdog is used to detect the occurrence of a software fault, usually generated
by external interferences or by unexpected logical conditions, which cause the application
program to abandon its normal sequence.
The window function can be used to trim the watchdog behavior to match the application
perfectly.
The application software must refresh the counter before time-out and during a limited time
window.
A reset is generated in two situations:
1. Timeout: At 16 MHz CPU clock the time-out period can be adjusted between 75 µs up to
64 ms.
2. Refresh out of window: The downcounter is refreshed before its value is lower than the
one stored in the window register.
Independent watchdog timer
The independent watchdog peripheral can be used to resolve processor malfunctions due to
hardware or software failures.
It is clocked by the 128 kHZ LSI internal RC clock source, and thus stays active even in case
of a CPU clock failure
The IWDG time base spans from 60 µs to 1 s.
4.8
Auto wakeup counter
Used for auto wakeup from active halt mode
•
Clock source: Internal 128 kHz internal low frequency RC oscillator or external clock
•
LSI clock can be internally connected to TIM1 input capture channel 1 for calibration
•
4.9
Beeper
The beeper function outputs a signal on the BEEP pin for sound generation. The signal is in
the range of 1, 2 or 4 kHz.
The beeper output port is only available through the alternate function remap option bit AFR7.
4.10
TIM1 - 16-bit advanced control timer
This is a high-end timer designed for a wide range of control applications. With its
complementary outputs, dead-time control and center-aligned PWM capability, the field of
applications is extended to motor control, lighting and half-bridge driver
16-bit up, down and up/down autoreload counter with 16-bit prescaler
•
Four independent capture/compare channels (CAPCOM) configurable as input capture,
output compare, PWM generation (edge and center aligned mode) and single pulse mode
output
•
DocID15590 Rev 8
15/116
STMICROELECTRONICS [ ST ]
