PIC18F-LF1XK50 MICROCHIP [Microchip Technology], PIC18F-LF1XK50 Datasheet - Page 108

• Manufacturer Part Number: PIC18F-LF1XK50
• Description: 20-Pin USB Flash Microcontrollers
• Manufacturer: MICROCHIP [Microchip Technology]

PIC18F/LF1XK50
11.3.2
The Timer1 oscillator circuit draws very little power
during operation. Due to the low-power nature of the
oscillator, it may also be sensitive to rapidly changing
signals in close proximity.
The oscillator circuit, shown in
located as close as possible to the microcontroller.
There should be no circuits passing within the oscillator
circuit boundaries other than V
If a high-speed circuit must be located near the oscilla-
tor (such as the CCP1 pin in Output Compare or PWM
mode, or the primary oscillator using the OSC2 pin), a
grounded guard ring around the oscillator circuit, as
shown in
single-sided PCB or in addition to a ground plane.
FIGURE 11-4:
11.4
The TMR1 register pair (TMR1H:TMR1L) increments
from 0000h to FFFFh and rolls over to 0000h. The
Timer1 interrupt, if enabled, is generated on overflow,
which is latched in the TMR1IF interrupt flag bit of the
PIR1 register. This interrupt can be enabled or disabled
by setting or clearing the TMR1IE Interrupt Enable bit
of the PIE1 register.
DS41350E-page 108
Note: Not drawn to scale.
Timer1 Interrupt
Figure
TIMER1 OSCILLATOR LAYOUT
CONSIDERATIONS
11-4, may be helpful when used on a
OSCILLATOR CIRCUIT
WITH GROUNDED
GUARD RING
SS
Figure
OSC1
RC0
V
V
OSC2
RC1
RC2
or V
DD
SS
DD
11-3, should be
.
Preliminary
information).
11.5
If either of the CCP modules is configured to use Timer1
and generate a Special Event Trigger in Compare mode
(CCP1M<3:0> or CCP2M<3:0> = 1011), this signal will
reset Timer1. The trigger from CCP2 will also start an
A/D conversion if the A/D module is enabled (see
Section 14.3.4 “Special Event Trigger”
The module must be configured as either a timer or a
synchronous counter to take advantage of this feature.
When used this way, the CCPRH:CCPRL register pair
effectively becomes a period register for Timer1.
If Timer1 is running in Asynchronous Counter mode,
this Reset operation may not work.
In the event that a write to Timer1 coincides with a
special Event Trigger, the write operation will take
precedence.
Note:
Resetting Timer1 Using the CCP
Special Event Trigger
The Special Event Triggers from the
CCP2 module will not set the TMR1IF
interrupt flag bit of the PIR1 register.
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