AC244026 Microchip Technology, AC244026 Datasheet - Page 142

• Manufacturer Part Number: AC244026
• Description: Processor Extension Pak (PIC16F727-ICE) 200K Device Emulator - Debugger Accessor
• Manufacturer: Microchip Technology
• Series: -r

Specifications of AC244026

• Accessory Type: Debug Interface Module
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• For Use With/related Products: PIC16LF727

PIC16F72X/PIC16LF72X
15.3.2
The PWM period is specified by the PR2 register of
Timer2. The PWM period can be calculated using the
formula of Equation 15-1.
EQUATION 15-1:
When TMR2 is equal to PR2, the following three events
occur on the next increment cycle:
• TMR2 is cleared
• The CCPx pin is set. (Exception: If the PWM duty
• The PWM duty cycle is latched from CCPRxL into
15.3.3
The PWM duty cycle is specified by writing a 10-bit value
to multiple registers: CCPRxL register and DCxB<1:0>
bits of the CCPxCON register. The CCPRxL contains
the eight MSbs and the DCxB<1:0> bits of the
CCPxCON register contain the two LSbs. CCPRxL and
DCxB<1:0> bits of the CCPxCON register can be written
to at any time. The duty cycle value is not latched into
CCPRxH until after the period completes (i.e., a match
between PR2 and TMR2 registers occurs). While using
the PWM, the CCPRxH register is read-only.
Equation 15-2 is used to calculate the PWM pulse
width.
Equation 15-3 is used to calculate the PWM duty cycle
ratio.
DS41341E-page 142
cycle = 0%, the pin will not be set.)
CCPRxH.
Note:
Note:
PWM Period
PWM PERIOD
The
Section 13.1 “Timer2 Operation”) is not
used in the determination of the PWM
frequency.
PWM DUTY CYCLE
T
OSC
Timer2
=
= 1/F
(TMR2 Prescale Value)
[
PWM PERIOD
(
PR2
OSC
)
+
postscaler
1
] 4 T
•
•
OSC
(refer
•
to
EQUATION 15-2:
EQUATION 15-3:
The CCPRxH register and a 2-bit internal latch are
used to double buffer the PWM duty cycle. This double
buffering is essential for glitchless PWM operation.
The 8-bit timer TMR2 register is concatenated with
either the 2-bit internal system clock (F
the prescaler, to create the 10-bit time base. The system
clock is used if the Timer2 prescaler is set to 1:1.
When the 10-bit time base matches the CCPRxH and
2-bit latch, then the CCPx pin is cleared (refer to
Figure 15-3).
Duty Cycle Ratio
Pulse Width
Note: T
OSC
=
= 1/F
(
T
=
CCPRxL:CCPxCON<5:4>
OSC
OSC
PULSE WIDTH
DUTY CYCLE RATIO
(
---------------------------------------------------------------------- -
CCPRxL:CCPxCON<5:4>
© 2009 Microchip Technology Inc.
•
(TMR2 Prescale Value)
4 PR2
(
+
OSC
1
)
), or 2 bits of
)
•
)