Z8F640x/Z8F480x/Z8F320x/Z8F240x/Z8F160x
Z8 Encore!®
58
Timer Block
Timer
Control
Data
Bus
Block
Control
16-Bit
Reload Register
Interrupt,
PWM,
and
Timer
Interrupt
Timer Output
Control
Timer
Output
System
Clock
16-Bit Counter
with Prescaler
Timer
Input
Gate
Input
16-Bit
PWM / Compare
Capture
Input
Figure 66. Timer Block Diagram
Operation
The timers are 16-bit up-counters. Minimum time-out delay is set by loading the value
0001Hinto the Timer Reload High and Low Byte registers and setting the prescale value
to 1. Maximum time-out delay is set by loading the value 0000Hinto the Timer Reload
High and Low Byte registers and setting the prescale value to 128. If the Timer reaches
FFFFH, the timer rolls over to 0000Hand continues counting.
Timer Operating Modes
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 0001H. Then, the timer is automatically disabled and
stops 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 desired to have the Timer Output make a permanent state change upon One-Shot time-
PS017610-0404
Timers
ZILOG [ ZILOG, INC. ]
