z8f0813 ZiLOG Semiconductor, z8f0813 Datasheet - Page 78

• Manufacturer Part Number: z8f0813
• Description: High-performance 8-bit Microcontrollers
• Manufacturer: ZiLOG Semiconductor

Operation
PS024314-0308
Timer Operating Modes
The timers are 16-bit up-counters. Minimum time-out delay is set by loading the value
0001H
to 1. Maximum time-out delay is set by loading the value
High and Low Byte registers and setting the prescale value to 128. If the Timer reaches
FFFFH
The timers can be 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. Upon reaching
the Reload value, the timer generates an interrupt and the count value in the Timer High
and Low Byte registers is reset to
counting.
Also, if the Timer Output alternate function is enabled, the Timer Output pin changes state
for one system clock cycle (from Low to High or from High to Low) upon timer Reload. If
it is appropriate to have the Timer Output make a state change at a One-Shot time-out
(rather than a single cycle pulse), first set the TPOL bit in the Timer Control register to the
start value before enabling ONE-SHOT mode. After starting the timer, set TPOL to the
opposite bit value.
Follow the steps below for configuring a timer for ONE-SHOT mode and initiating the
count:
1. Write to the Timer Control register to:
2. Write to the Timer 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.
4. If appropriate, enable the timer interrupt and set the timer interrupt priority by writing
5. If using the Timer Output function, configure the associated GPIO port pin for the
–
–
–
–
to the relevant interrupt registers.
Timer Output alternate function.
, the timer rolls over to
into the Timer Reload High and Low Byte registers and setting the prescale value
Disable the timer
Configure the timer for ONE-SHOT mode
Set the prescale value
Set the initial output level (High or Low) if using the Timer Output alternate
function
0000H
0001H
and continues counting.
. The timer is automatically disabled and stops
Z8 Encore! XP
0000H
Product Specification
into the Timer Reload
®
F0823 Series
Timers
68