z16f2811 ZiLOG Semiconductor, z16f2811 Datasheet - Page 110

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

Operation
PS022006-0207
Timer Operating Modes
The general-purpose timer is a 16-bit up-counter. In normal operation, the timer is
initialized to
reload high and low byte registers, then resets to
continues depending on the mode.
Minimum time-out delay (1 system clock) is set by loading the value
Timer Reload High and Low byte registers and setting the prescale value to 1.
Maximum time-out delay (2
the Timer Reload High and Low byte registers and setting the prescale value to 128. When
the timer reaches
If the reload register is set to a value less than the current counter value, the counter
continues counting until it reaches
continues to count until it reaches the reload value and it resets to
The timers are configured to operate in the following modes:
ONE-SHOT Mode
In ONE-SHOT mode, the timer counts up to the 16-bit reload value stored in the Timer
Reload High and Low byte registers. The timer input is the system clock. When the timer
reaches the reload value, it generates an interrupt and the count value in the Timer High
and Low byte registers is reset to
counting.
If the timer output alternate function is enabled, the timer output pin changes state for one
system clock cycle (from Low to High then back to Low if TPOL = 0) at timer Reload. If
the timer output is required to make a permanent state change on ONE-SHOT timeout,
first set the TPOL bit in the timer control 1 register to the start value before beginning
ONE-SHOT mode. Then, after starting the timer, set TPOL to the opposite value.
Follow the steps below to configure a timer for ONE-SHOT mode and initiate the counts:
1. Write to the timer control registers to:
2. Write to the timer high and low byte registers to set the starting count value.
–
–
–
–
–
Disable the timer.
Configure the timer for ONE-SHOT mode.
Set the prescale value.
Set the initial output level (High or Low) using the TPOL bit for the timer output
alternate function.
Set the INTERRUPT mode.
0001H
FFFFH
. When the timer is enabled, it counts up to the value contained in the
, the timer rolls over to
P R E L I M I N A R Y
16
* 2
0001H
7
FFFFH
system clocks) is set by loading the value
. The timer is automatically disabled and stops
, and then resets to
0000H
0001H
.
. The counter either halts or
0000H
Product Specification
0001H
ZNEO
. Then the timer
0001H
.
™
Z16F Series
into the
0000H
Timers
into
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