Z8F1680SH020SG Datasheet, PDF (131/412 Pages) Zilog, Inc. – High-Performance 8-Bit Microcontrollers

Z8 Encore! XP^® F1680 Series
Product Specification
106
9.2.4. Reading the Timer Count Values
The current count value in the timers can be read while counting (enabled). This capability
has no effect on timer operation. When the timer is enabled and the Timer High Byte
register is read, the contents of the Timer Low Byte Register are placed in a holding
register. A subsequent read from the Timer Low Byte Register returns the value in the
holding register. This operation allows accurate reads of the full 16-bit timer count value
while enabled. When the timers are not enabled, a read from the Timer Low Byte Register
returns the actual value in the counter.
9.2.5. Timer Output Signal Operation
The Timer Output is a GPIO port pin alternate function. Generally, the Timer Output is
toggled every time the counter is reloaded.
9.2.6. Timer Noise Filter
A Noise Filter circuit is included which filters noise on a Timer Input signal before the
data is sampled by the block.
The Noise Filter has the following features:
• Synchronizes the receive input data to the Timer Clock
• NFEN (Noise Filter Enable) input selects whether the Noise Filter is bypassed
(NFEN=0) or included (NFEN=1) in the receive data path
• NFCTL (Noise Filter Control) input selects the width of the up/down saturating counter
digital filter. The available widths range from 4 bits to 11 bits
• The digital filter output has hysteresis
• Provides an active Low saturated state output (FiltSatB) which is used as an indication
of the presence of noise
• Available for operation in STOP Mode
9.2.7. Architecture
Figure 12 displays how the Noise Filter is integrated with the Timer.
PS025015-1212
PRELIMINARY
Timers