PIC16F88-I/SO Microchip Technology Inc., PIC16F88-I/SO Datasheet - Page 87

• Manufacturer Part Number: PIC16F88-I/SO
• Description: 18 PIN, 7 KB FLASH, 368 RAM, 16 I/O
• Manufacturer: Microchip Technology Inc.

Specifications of PIC16F88-I/SO

• A/d Inputs: 7-Channel, 10-Bit
• Comparators: 2
• Cpu Speed: 5 MIPS
• Eeprom Memory: 256 Bytes
• Input Output: 16
• Interface: I2C/SPI/USART
• Memory Type: Flash
• Number Of Bits: 8
• Package Type: 18-pin SOIC
• Programmable Memory: 7K Bytes
• Ram Size: 368 Bytes
• Speed: 20 MHz
• Timers: 2-8-bit, 1-16-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 following formula.
EQUATION 9-3:
TABLE 9-3:
TABLE 9-4:
 2005 Microchip Technology Inc.
0Bh,8Bh
10Bh,18Bh
0Ch
8Ch
86h
11h
92h
12h
15h
16h
17h
Legend:
Note 1:
Timer Prescaler (1, 4, 16)
PR2 Value
Maximum Resolution (bits)
Address
Note:
Resolution
INTCON
PIR1
PIE1
TRISB
TMR2
PR2
T2CON
CCPR1L
CCPR1H
CCP1CON
x = unknown, u = unchanged, - = unimplemented, read as ‘0’. Shaded cells are not used by PWM and Timer2.
This bit is only implemented on the PIC16F88. The bit will read ‘0’ on the PIC16F87.
If the PWM duty cycle value is longer than
the PWM period, the CCP1 pin will not be
cleared.
Name
PWM Frequency
EXAMPLE PWM FREQUENCIES AND RESOLUTIONS AT 20 MHz
REGISTERS ASSOCIATED WITH PWM AND TIMER2
=
PORTB Data Direction Register
Timer2 Module Register
Timer2 Period Register
Capture/Compare/PWM Register 1 (LSB)
Capture/Compare/PWM Register 1 (MSB)
Bit 7
GIE
—
—
—
—
log
TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000 -000 0000
(
log(2)
ADIE
ADIF
PEIE
Bit 6
F
F
—
PWM
OSC
(1)
(1)
)
TMR0IE
CCP1X
bits
RCIF
RCIE
Bit 5
1.22 kHz 4.88 kHz 19.53 kHz 78.12 kHz 156.3 kHz 208.3 kHz
0xFF
CCP1Y
16
10
INT0IE
TXIE
Bit 4
TXIF
CCP1M3 CCP1M2 CCP1M1 CCP1M0 --00 0000 --00 0000
0xFF
SSPIE
SSPIF
RBIE
Bit 3
10
4
9.3.3
The following steps should be taken when configuring
the CCP module for PWM operation:
1.
2.
3.
4.
5.
Note:
Set the PWM period by writing to the PR2
register.
Set the PWM duty cycle by writing to the
CCPR1L register and CCP1CON<5:4> bits.
Make the CCP1 pin an output by clearing the
TRISB<x> bit.
Set the TMR2 prescale value and enable Timer2
by writing to T2CON.
Configure the CCP1 module for PWM operation.
TMR0IF
CCP1IF
CCP1IE
Bit 2
0xFF
10
1
SETUP FOR PWM OPERATION
The TRISB bit (0 or 3) is dependant upon
the
(CCPMX).
TMR2IF
TMR2IE
INT0IF
Bit 1
setting
0x3F
PIC16F87/88
1
8
TMR1IF
TMR1IE -000 0000 -000 0000
Bit 0
RBIF
of
configuration
0x1F
0000 000x 0000 000u
-000 0000 -000 0000
1111 1111 1111 1111
0000 0000 0000 0000
1111 1111 1111 1111
xxxx xxxx uuuu uuuu
xxxx xxxx uuuu uuuu
POR, BOR
Value on
1
7
DS30487C-page 85
0x17
Value on
all other
bit
6.6
Resets
1
12