ST72521 STMICROELECTRONICS [STMicroelectronics], ST72521 Datasheet - Page 64

• Manufacturer Part Number: ST72521
• Description: 8-BIT MCU WITH NESTED INTERRUPTS, FLASH, 10-BIT ADC, FIVE TIMERS, SPI, SCI, I2C, CAN INTERFACE
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

ST72521
PWM AUTO-RELOAD TIMER (Cont’d)
Output compare and Time base interrupt
On overflow, the OVF flag of the ARTCSR register
is set and an overflow interrupt request is generat-
ed if the overflow interrupt enable bit, OIE, in the
ARTCSR register, is set. The OVF flag must be re-
set by the user software. This interrupt can be
used as a time base in the application.
Figure 40. External Event Detector Example (3 counts)
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f
EXT
COUNTER
=f
COUNTER
OVF
FDh
FEh
ARTARR=FDh
FFh
INTERRUPT
IF OIE=1
FDh
External clock and event detector mode
Using the f
auto-reload timer can be used as an external clock
event detector. In this mode, the ARTARR register
is used to select the n
be counted before setting the OVF flag.
When entering HALT mode while f
all the timer control registers are frozen but the
counter continues to increment. If the OIE bit is
set, the next overflow of the counter will generate
an interrupt which wakes up the MCU.
ARTCSR READ
FEh
EXT
n
EVENT
external prescaler input clock, the
FFh
INTERRUPT
IF OIE=1
= 256 - ARTARR
EVENT
FDh
number of events to
ARTCSR READ
EXT
is selected,
t