PIC18F6621-I/PT Microchip Technology Inc., PIC18F6621-I/PT Datasheet - Page 157

• Manufacturer Part Number: PIC18F6621-I/PT
• Description: 64 PIN, 64 KB FLASH, 3840 RAM, 52 I/O
• Manufacturer: Microchip Technology Inc.

Specifications of PIC18F6621-I/PT

• A/d Inputs: 12-Channel, 10-Bit
• Comparators: 2
• Cpu Speed: 10 MIPS
• Eeprom Memory: 1024 Bytes
• Input Output: 54
• Interface: I2C/SPI/UART/USART
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 64-pin TQFP
• Programmable Memory: 64K Bytes
• Ram Size: 3.8K Bytes
• Speed: 40 MHz
• Timers: 2-8-bit, 3-16-bit
• Voltage, Range: 2-5.5 V
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

The maximum PWM resolution (bits) for a given PWM
frequency is given by the equation:
EQUATION 16-3:
TABLE 16-3:
 2005 Microchip Technology Inc.
Timer Prescaler (1, 4, 16)
PR2 Value
Maximum Resolution (bits)
Note:
PWM Resolution (max)
PWM Frequency
If the PWM duty cycle value is longer than
the PWM period, the CCP4 pin will not be
cleared.
EXAMPLE PWM FREQUENCIES AND RESOLUTIONS AT 40 MHz
=
log
-----------------------------bits
log


2.44 kHz
---------------
F
F
PWM
2 ( )
OSC
FFh
16
14


PIC18F6525/6621/8525/8621
9.77 kHz
FFh
12
4
39.06 kHz
16.4.3
The following steps should be taken when configuring
the CCP module for PWM operation:
1.
2.
3.
4.
5.
6.
FFh
10
1
Select TMR2 or TMR4 by setting or clearing the
T3CCP2:T3CCP1 bits in the T3CON register.
Set the PWM period by writing to the PR2 or
PR4 register
Set the PWM duty cycle by writing to the
CCPR4L register and CCP4CON<5:4> bits.
Make the CCP4 pin an output by clearing the
TRISG<3> bit.
Set TMR2 or TMR4 prescale value, enable
Timer2 or Timer4 by writing to T2CON or
T4CON.
Configure the CCP4 module for PWM operation.
SETUP FOR PWM OPERATION
156.25 kHz
3Fh
1
8
312.50 kHz
1Fh
1
7
DS39612B-page 155
416.67 kHz
6.58
17h
1