Z8F082ASJ020EG Datasheet, PDF (101/282 Pages) Zilog, Inc. – High-Performance 8-Bit Microcontrollers

Z8 Encore! XP^® F082A Series
Product Specification
84
– Set the Capture edge (rising or falling) for the Timer Input
2. Write to the Timer High and Low Byte registers to set the starting count value (typi-
cally 0001H).
3. Write to the Timer Reload High and Low Byte registers to set the Compare value.
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 gen-
erated only at the input capture event or the reload event by setting TICONFIG field
of the TxCTL0 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 inter-
rupt 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
Elapsed
Time
(s)
=
_---C_-----a_---p_----t_--u_----r_--e_------V_----a_----l_-u_----e_-----–_-----S_----t_--a_----r_--t_----V_----a_----l_-u_----e_----_----_----P_-----r_--e_----s_---c_---a_----l_--e_--
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 reg-
ister. 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
The timer output function is a GPIO port pin alternate function. The Timer Output is tog-
gled every time the counter is reloaded.
PS022827-1212
PRELIMINARY
Operation