z16f2811 ZiLOG Semiconductor, z16f2811 Datasheet - Page 113

• Manufacturer Part Number: z16f2811
• Description: High Performance Microcontrollers
• Manufacturer: ZiLOG Semiconductor

PS022006-0207
Caution:
Caution:
If an initial starting value other than
registers, use the ONE-SHOT mode equation to determine the first timeout period.
COUNTER and COMPARATOR COUNTER Modes
In COUNTER mode, the timer counts input transitions from a GPIO port pin. The timer
input is taken from the associated GPIO port pin. The TPOL bit in the timer control 1
register selects whether the count occurs on the rising edge or the falling edge of the timer
input signal. In COUNTER mode, the prescaler is disabled.
The input frequency of the timer input signal must not exceed one-fourth the
system clock frequency.
In COMPARATOR COUNTER mode, the timer counts output transitions from an analog
comparator output. The timer takes its input from the output of the comparator. The TPOL
bit in the timer control 1 register selects whether the count occurs on the rising edge or the
falling edge of the comparator output signal. The prescaler is disabled in the
COMPARATOR COUNTER mode.
The frequency of the comparator output signal must not exceed one-fourth the
system clock frequency.
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
If the timer output alternate function is enabled, the timer output pin changes state (from
Low to High or High to Low) at timer Reload.
Follow the steps below to configure a timer for COUNTER and COMPARATOR
COUNTER modes and initiate the count:
1. Write to the timer control registers to:
2. Write to the timer reload high and low byte registers to set the starting count value.
3. Write to the timer reload high and low byte registers to set the Reload value.
–
–
–
This affects only the first pass in the COUNTER modes. After the first timer Reload,
counting always begins at the reset value of
0001H
Disable the timer.
Configure the timer for COUNTER or COMPARATOR COUNTER mode.
Select either the rising edge or falling edge of the timer input or comparator output
signal for the count. This also sets the initial logic level (High or Low) for the
timer output alternate function. However, you need not enable the timer output
function.
and counting resumes.
P R E L I M I N A R Y
0001H
is loaded into the timer high and low byte
0001H
.
Product Specification
ZNEO
™
Z16F Series
Timers
99