PIC18F6490-E/PT Microchip Technology, PIC18F6490-E/PT Datasheet - Page 155

• Manufacturer Part Number: PIC18F6490-E/PT
• Description: IC PIC MCU FLASH 16KX16 64TQFP
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18F6490-E/PT

• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 40MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, HLVD, LCD, POR, PWM, WDT
• Number Of I /o: 50
• Program Memory Size: 16KB (8K x 16)
• Program Memory Type: FLASH
• Ram Size: 768 x 8
• Voltage - Supply (vcc/vdd): 4.2 V ~ 5.5 V
• Data Converters: A/D 12x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 64-TFQFP
• For Use With: DM163028 - BOARD DEMO PICDEM LCD
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -

14.4
In Pulse-Width Modulation (PWM) mode, the CCP2 pin
produces up to a 10-bit resolution PWM output. Since
the CCP2 pin is multiplexed with a PORTC or PORTE
data latch, the appropriate TRIS bit must be cleared to
make the CCP2 pin an output.
Figure 14-4 shows a simplified block diagram of the
CCP2 module in PWM mode.
For a step-by-step procedure on how to set up the CCP
module for PWM operation, see Section 14.4.3
“Setup for PWM Operation”.
FIGURE 14-4:
© 2007 Microchip Technology Inc.
Note 1: The 8-bit TMR2 value is concatenated with the 2-bit
Note:
CCPR2H (Slave)
CCPR2L
Comparator
Duty Cycle Registers
TMR2
PR2
Comparator
PWM Mode
internal Q clock, or 2 bits of the prescaler, to create the
10-bit time base.
Clearing the CCP2CON register will force
the RC1 or RE7 output latch (depending
on device configuration) to the default low
level. This is not the PORTC or PORTE
I/O data latch.
(Note 1)
Clear Timer,
CCP2 pin and
latch D.C.
SIMPLIFIED PWM BLOCK
DIAGRAM
CCP2CON<5:4>
R
S
Q
TRISC<2>
PIC18F6390/6490/8390/8490
CCP2
A PWM output (Figure 14-5) has a time base (period)
and a time that the output stays high (duty cycle). The
frequency of the PWM is the inverse of the period
(1/period).
FIGURE 14-5:
14.4.1
The PWM period is specified by writing to the PR2
register. The PWM period can be calculated using the
following formula:
EQUATION 14-1:
PWM frequency is defined as 1/[PWM period].
When TMR2 is equal to PR2, the following three events
occur on the next increment cycle:
• TMR2 is cleared
• The CCP2 pin is set (exception: if PWM duty
• The PWM duty cycle is latched from CCPR2L into
cycle = 0%, the CCP2 pin will not be set)
CCPR2H
Note:
PWM Period = (PR2) + 1] • 4 • T
TMR2 = PR2
Duty Cycle
PWM PERIOD
The Timer2 postscalers (see Section 12.0
“Timer2 Module”) are not used in the
determination of the PWM frequency. The
postscaler could be used to have a servo
update rate at a different frequency than
the PWM output.
Period
TMR2 = Duty Cycle
(TMR2 Prescale Value)
PWM OUTPUT
TMR2 = PR2
DS39629C-page 153
OSC
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