Z8 Encore! XP® F08xA Series
Product Specification
71
4. Enable the timer interrupt, if appropriate, and set the timer interrupt priority by writing
to the relevant interrupt registers.By default, the timer interrupt are generated for both
input capture and reload events. If appropriate, configure the timer interrupt to be
generated only at the input capture event or the reload event by setting TICONFIG
field of the TxCTL1 register.
5. Configure the associated GPIO port pin for the Timer Input alternate function.
6. Write to the Timer Control register to enable the timer.
7. Counting begins on the first appropriate transition of the Timer Input signal. No
interrupt is generated by this first edge.
In CAPTURE/COMPARE mode, the elapsed time from timer start to Capture event can be
calculated using the following equation:
(Capture Value – Start Value) × Prescale
---------------------------------------------------------------------------------------------------------
Capture Elapsed Time (s) =
System Clock Frequency (Hz)
Reading the Timer Count Values
The current count value in the timers can be read while counting (enabled). This capability
has no effect on timer operation. When the timer is enabled and the Timer High Byte reg-
ister is read, the contents of the Timer Low Byte register are placed in a holding register. A
subsequent read from the Timer Low Byte register returns the value in the holding register.
This operation allows accurate reads of the full 16-bit timer count value while enabled.
When the timers are not enabled, a read from the Timer Low Byte register returns the
actual value in the counter.
Timer Pin Signal Operation
Timer Output is a GPIO Port pin alternate function. The Timer Output is toggled every
time the counter is reloaded.
The timer input can be used as a selectable counting source. It shares the same pin as the
complementary timer output. When selected by the GPIO Alternate Function Registers,
this pin functions as a timer input in all modes except for the DUAL PWM OUTPUT
mode. For this mode, there is no timer input available.
PS024705-0405
P R E L I M I N A R Y
Timers
ZILOG [ ZILOG, INC. ]
