z8f083a ZiLOG Semiconductor, z8f083a Datasheet - Page 81

• Manufacturer Part Number: z8f083a
• Description: High-performance 8-bit Microcontrollers
• Manufacturer: ZiLOG Semiconductor

PS026308-1207
Caution:
Counter Mode Timer Input Transitions
2. Write to the timer high and low byte registers to set the starting count value. This only
3. Write to the timer reload high and low byte registers to set the reload value.
4. If appropriate, enable the timer interrupt and set the timer interrupt priority by writing
5. Configure the associated GPIO port pin for the timer input alternate function.
6. If using the timer output function, configure the associated GPIO port pin for the timer
7. Write to the timer control register to enable the timer.
In COUNTER mode, the number of timer input transitions is given by the following
equation:
COMPARATOR COUNTER Mode
In COMPARATOR COUNTER mode, the timer counts the input transitions from the
analog comparator output. The TPOL bit in the timer control register determines whether
the count occurs on the rising edge or the falling edge of the comparator output signal. In
COMPARATOR COUNTER mode, the prescaler is disabled.
After reaching the reload value stored in the timer reload high and low byte registers, the
timer generates an interrupt, the count value in the timer high and low byte registers is
reset to
enabled, the timer output pin changes state (from low to high or from high to low) at timer
reload.
The steps for configuring a timer for COMPARATOR COUNTER mode and for initiating
the count are as follows:
1. Write to the timer control register to:
The frequency of the comparator output signal must not exceed one-fourth the system
clock frequency.
–
affects the first pass in COUNTER mode. After the first timer reload in COUNTER
mode, counting always begins at the reset value
timer high and low byte registers must be written with the value
to the relevant interrupt registers.
output alternate function.
–
–
0001H
Select either the rising edge or falling edge of the timer input signal for the count.
This selection also sets the initial logic level (high or low) for the timer output
alternate function. However, the timer output function is not required to be
enabled
Disable the timer
Configure the timer for COMPARATOR COUNTER mode
and counting resumes. Also, if the timer output alternate function is
=
Current Count Value Start Value
0001H
Z8 Encore!
. In COUNTER mode, the
Product Specification
0001H
–
®
F083A Series
.
Timers
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