PIC16F628A-I/SO Microchip Technology, PIC16F628A-I/SO Datasheet - Page 61

• Manufacturer Part Number: PIC16F628A-I/SO
• Description: IC MCU FLASH 2KX14 EEPROM 18SOIC
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F628A-I/SO

• Program Memory Type: FLASH
• Program Memory Size: 3.5KB (2K x 14)
• Package / Case: 18-SOIC (7.5mm Width)
• 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
• 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 ~ 85°C
• Processor Series: PIC16F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 224 B
• Interface Type: SCI/USART
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 16
• Number Of Timers: 3
• Operating Supply Voltage: 2 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120, ICE2000, DM163014, DM164120-4
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: XLT18SO-1 - SOCKET TRANSITION 18SOIC 300MILI3DBF648 - BOARD DAUGHTER ICEPIC3AC162053 - HEADER INTERFACE ICD,ICD2 18DIPAC164010 - MODULE SKT PROMATEII DIP/SOIC
• Data Converters: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

9.3.2
The PWM duty cycle is specified by writing to the
CCPR1L register and to the CCP1CON<5:4> bits. Up
to 10-bit resolution is available: the CCPR1L contains
the eight MSbs and the CCP1CON<5:4> contains the
two LSbs. This 10-bit value is represented by
CCPR1L:CCP1CON<5:4>. The following equation is
used to calculate the PWM duty cycle in time:
CCPR1L and CCP1CON<5:4> can be written to at any
time, but the duty cycle value is not latched into
CCPR1H until after a match between PR2 and TMR2
occurs (i.e., the period is complete). In PWM mode,
CCPR1H is a read-only register.
The CCPR1H register and a 2-bit internal latch are
used to double buffer the PWM duty cycle. This double
buffering is essential for glitch less PWM operation.
When the CCPR1H and 2-bit latch match TMR2
concatenated with an internal 2-bit Q clock or 2 bits of
the TMR2 prescaler, the CCP1 pin is cleared.
TABLE 9-3:
TABLE 9-4:
 2004 Microchip Technology Inc.
0Bh, 8Bh,
10Bh, 18Bh
0Ch
8Ch
86h, 186h
11h
92h
12h
15h
16h
17h
Legend:
Timer Prescaler (1, 4, 16)
PR2 Value
Maximum Resolution (bits)
PWM duty cycle =
Address
(CCPR1L:CCP1CON<5:4>) Tosc TMR2 prescale
x = unknown, u = unchanged, - = unimplemented read as ‘0’. Shaded cells are not used by PWM and Timer2.
INTCON
PIR1
PIE1
TRISB
TMR2
PR2
T2CON
CCPR1L
CCPR1H
CCP1CON
PWM DUTY CYCLE
Name
PWM Frequency
EXAMPLE PWM FREQUENCIES AND RESOLUTIONS AT 20 MHz
REGISTERS ASSOCIATED WITH PWM AND TIMER2
Bit 7
EEIE
EEIF
GIE
—
—
TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0
Bit 6
CMIF
CMIE
PEIE
—
CCP1X
Bit 5
RCIF
RCIE
T0IE
value
Capture/Compare/PWM register1 (MSB)
Capture/Compare/PWM register1 (LSB)
PORTB Data Direction Register
Timer2 module’s period register
1.22 kHz 4.88 kHz 19.53 kHz 78.12 kHz 156.3 kHz 208.3 kHz
Timer2 module’s register
0xFF
CCP1Y
16
10
Bit 4
INTE
TXIF
TXIE
Preliminary
PIC16F627A/628A/648A
CCP1M3
Bit 3
0xFF
RBIE
—
—
10
4
Maximum PWM resolution (bits) for a given PWM
frequency:
For an example PWM period and duty cycle
calculation, see the PICmicro
Manual (DS33023).
9.3.3
The following steps should be taken when configuring
the CCP module for PWM operation:
1.
2.
3.
4.
5.
Note:
PWM
Resolution
TMR2ON T2CKPS1 T2CKPS0 -000 0000
CCP1M2
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<3> bit.
Set the TMR2 prescale value and enable Timer2
by writing to T2CON.
Configure the CCP1 module for PWM operation.
CCP1IE
CCP1IF
Bit 2
T0IF
0xFF
10
1
If the PWM duty cycle value is longer than
the PWM period the CCP1 pin will not be
cleared.
SET-UP FOR PWM OPERATION
CCP1M1 CCP1M0
TMR2IE
TMR2IF
=
Bit 1
INTF
log
-------------------------------------------------------------------------- - bits


0x3F
-------------------------------------------------------------
Fpwm TMR2 Prescaler
1
8
TMR1IF
TMR1IE
Bit 0
RBIF
log(2)
®
Fosc
0000 000x
0000 -000
0000 -000
1111 1111
0000 0000
1111 1111
xxxx xxxx
xxxx xxxx
--00 0000
Mid-Range Reference
Value on
0x1F
POR
1
7
DS40044B-page 59
0000 000u
0000 -000
0000 -000
1111 1111
0000 0000
1111 1111
uuuu uuuu
uuuu uuuu
uuuu uuuu
--00 0000


Value on
all other
Resets
0x17
6.5
1