z8f0813 ZiLOG Semiconductor, z8f0813 Datasheet - Page 83

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

PS024314-0308
If an initial starting value other than
registers, use the ONE-SHOT mode equation to determine the first PWM time-out period.
If TPOL is set to 0, the ratio of the PWM output High time to the total period is
represented by the following equation:
If TPOL is set to 1, the ratio of the PWM output High time to the total period is
represented by the following equation:
PWM Dual Output Mode
In PWM DUAL OUTPUT mode, the timer outputs a PWM output signal pair (basic PWM
signal and its complement) through two GPIO port pins. The timer input is the system
clock. The timer first counts up to the 16-bit PWM match value stored in the Timer PWM
High and Low Byte registers. When the timer count value matches the PWM value, the
Timer Output toggles. The timer continues counting until it reaches the Reload value
stored in the Timer Reload High and Low Byte registers. Upon reaching the Reload value,
the timer generates an interrupt, the count value in the Timer High and Low Byte registers
is reset to
If the TPOL bit in the Timer Control register is set to 1, the Timer Output signal begins as
a High (1) and transitions to a Low (0) when the timer value matches the PWM value. The
Timer Output signal returns to a High (1) after the timer reaches the Reload value and is
reset to
If the TPOL bit in the Timer Control register is set to 0, the Timer Output signal begins as
a Low (0) and transitions to a High (1) when the timer value matches the PWM value. The
Timer Output signal returns to a Low (0) after the timer reaches the Reload value and is
reset to
The timer also generates a second PWM output signal Timer Output Complement. The
Timer Output Complement is the complement of the Timer Output PWM signal. A
programmable deadband delay can be configured to time delay (0 to 128 system clock
cycles) PWM output transitions on these two pins from a low to a high (inactive to active).
This ensures a time gap between the deassertion of one PWM output to the assertion of its
complement.
Follow the steps below for configuring a timer for PWM Dual Output mode and initiating
the PWM operation:
1. Write to the Timer Control register to:
–
–
–
PWM Output High Time Ratio (%)
PWM Output High Time Ratio (%)
0001H
0001H
Disable the timer
Configure the timer for PWM Dual Output mode. Setting the mode also involves
writing to TMODEHI bit in TxCTL1 register
Set the prescale value
0001H
.
.
and counting resumes.
0001H
=
=
is loaded into the Timer High and Low Byte
----------------------------------- - 100
Reload Value
Reload Value
------------------------------------------------------------------ -
PWM Value
Reload Value
Z8 Encore! XP
×
–
PWM Value
Product Specification
®
×
F0823 Series
100
Timers
73