PIC16F628AT-E/SS Microchip Technology, PIC16F628AT-E/SS Datasheet - Page 60

• Manufacturer Part Number: PIC16F628AT-E/SS
• Description: IC,MICROCONTROLLER,8-BIT,PIC CPU,CMOS,SSOP,20PIN,PLASTIC
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F628AT-E/SS

• Rohs Compliant: YES
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 16
• Program Memory Size: 3.5KB (2K x 14)
• Program Memory Type: FLASH
• Eeprom Size: 128 x 8
• Ram Size: 224 x 8
• Voltage - Supply (vcc/vdd): 3 V ~ 5.5 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 20-SSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: I3DBF648 - BOARD DAUGHTER ICEPIC3AC162053 - HEADER INTERFACE ICD,ICD2 18DIP
• Data Converters: -
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

PIC16F627A/628A/648A
9.3
In Pulse Width Modulation (PWM) mode, the CCP1 pin
produces up to a 10-bit resolution PWM output. Since
the CCP1 pin is multiplexed with the PORTB data latch,
the TRISB<3> bit must be cleared to make the CCP1
pin an output.
Figure 9-3 shows a simplified block diagram of the
CCP module in PWM mode.
For a step by step procedure on how to set up the CCP
module for PWM operation, see Section 9.3.3 “Set-
Up for PWM Operation”.
FIGURE 9-3:
DS40044G-page 60
Note:
Note
CCPR1L
CCPR1H (Slave)
Comparator
Duty cycle registers
PR2
TMR2
1:
Comparator
PWM Mode
Clearing the CCP1CON register will force
the CCP1 PWM output latch to the default
low level. This is not the PORTB I/O data
latch.
8-bit timer is concatenated with 2-bit internal Q
clock or 2 bits of the prescaler to create 10-bit
time base.
(1)
Clear Timer,
CCP1 pin and
latch D.C.
SIMPLIFIED PWM BLOCK
DIAGRAM
CCP1CON<5:4>
R
S
Q
TRISB<3>
RB3/CCP1
A PWM output (Figure 9-4) 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
(frequency = 1/period).
FIGURE 9-4:
9.3.1
The PWM period is specified by writing to the PR2
register. The PWM period can be calculated using the
following formula:
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 CCP1 pin is set (exception: if PWM duty
• The PWM duty cycle is latched from CCPR1L into
PWM period
cycle = 0%, the CCP1 pin will not be set)
CCPR1H
Note:
TMR2 = PR2
Duty Cycle
PWM PERIOD
The Timer2 postscaler (see Section 8.0
“Timer2 Module”) is 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
[
(
PR2
TMR2 = Duty Cycle
PWM OUTPUT
)
© 2009 Microchip Technology Inc.
+
1
TMR2 = PR2
] 4 ⋅ ⋅
Tosc TMR2 prescale
⋅
value