z8f1621 ZiLOG Semiconductor, z8f1621 Datasheet - Page 97

• Manufacturer Part Number: z8f1621
• Description: High Performance 8-bit Microcontrollers
• Manufacturer: ZiLOG Semiconductor

PS019921-0308
The timer continues counting up to the 16-bit Reload value stored in the Timer Reload
High and Low Byte registers. Upon reaching the Reload value, the timer generates an
interrupt and continues counting.
Follow the steps below for configuring a timer for CAPTURE mode and initiating the
count:
1. Write to the Timer Control 1 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. Clear the Timer PWM High and Low Byte registers to 0000H. This allows the
5. If desired, enable the timer interrupt and set the timer interrupt priority by writing to
6. Configure the associated GPIO port pin for the Timer Input alternate function.
7. Write to the Timer Control 1 register to enable the timer and initiate counting.
In CAPTURE mode, the elapsed time from timer start to Capture event can be calculated
using the following equation:
COMPARE Mode
In COMPARE mode, the timer counts up to the 16-bit maximum Compare value stored in
the Timer Reload High and Low Byte registers. The timer input is the system clock. Upon
reaching the Compare value, the timer generates an interrupt and counting continues (the
timer value is not reset to
the Timer Output pin changes state (from Low to High or from High to Low) upon Com-
pare.
If the Timer reaches
Capture Elapsed Time (s)
–
–
–
–
(typically
software to determine if interrupts were generated by either a capture event or a
reload. If the PWM High and Low Byte registers still contain 0000H after the
interrupt, then the interrupt was generated by a Reload.
the relevant interrupt registers.
Disable the timer
Configure the timer for CAPTURE mode.
Set the prescale value.
Set the Capture edge (rising or falling) for the Timer Input.
0001H
FFFFH
).
0001H
, the timer rolls over to
=
(
-------------------------------------------------------------------------------------------------- -
Capture Value Start Value
). Also, if the Timer Output alternate function is enabled,
System Clock Frequency (Hz)
–
0000H
Z8 Encore! XP
)
and continue counting.
×
Prescale
Product Specification
®
F64XX Series
Timers
83