PIC18F87J72-I/PT Microchip Technology, PIC18F87J72-I/PT Datasheet - Page 163

• Manufacturer Part Number: PIC18F87J72-I/PT
• Description: IC PIC MCU 8BIT 14KB FLSH 80TQFP
• Manufacturer: Microchip Technology
• Series: PIC® 18Fr

Specifications of PIC18F87J72-I/PT

• Program Memory Type: FLASH
• Program Memory Size: 128KB (64K x 16)
• Package / Case: 80-TQFP
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 48MHz
• Connectivity: I²C, LIN, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, LCD, LVD, POR, PWM, WDT
• Number Of I /o: 51
• Ram Size: 3.8K x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 3.6 V
• Data Converters: A/D 12x12b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Data Bus Width: 8 bit
• Data Ram Size: 4 KB
• Interface Type: SPI, USART, SPI, I2C
• Maximum Clock Frequency: 8 MHz
• Number Of Programmable I/os: 51
• Number Of Timers: 4
• Operating Supply Voltage: 2 V to 3.6 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 14
• Controller Family/series: PIC18F
• No. Of I/o's: 51
• Ram Memory Size: 3923Byte
• Cpu Speed: 48MHz
• No. Of Timers: 4
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

16.4
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 16-4 shows a simplified block diagram of the
CCP1 module in PWM mode.
For a step-by-step procedure on how to set up the CCP
module for PWM operation, see Section 16.4.3
“Setup for PWM Operation”.
FIGURE 16-4:
 2010 Microchip Technology Inc.
Note 1:
Note:
CCPR1H (Slave)
Duty Cycle Registers
Comparator
CCPR1L
TMR2
PR2
Comparator
PWM Mode
The 8-bit TMR2 value is concatenated with the 2-bit
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,
CCP1 pin and
latch D.C.
SIMPLIFIED PWM BLOCK
DIAGRAM
CCP1CON<5:4>
R
S
Q
TRISC<2>
RC2/CCP1
Preliminary
PIC18F87J72 FAMILY
A PWM output (Figure 16-5) 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 16-5:
16.4.1
The PWM period is specified by writing to the PR2
register. The PWM period can be calculated using the
following formula:
EQUATION 16-1:
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 13.0
“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
DS39979A-page 163
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