PIC16F884-I/PT Microchip Technology, PIC16F884-I/PT Datasheet - Page 131

• Manufacturer Part Number: PIC16F884-I/PT
• Description: IC PIC MCU FLASH 4KX14 44TQFP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F884-I/PT

• Program Memory Type: FLASH
• Program Memory Size: 7KB (4K x 14)
• Package / Case: 44-TQFP, 44-VQFP
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 35
• Eeprom Size: 256 x 8
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 5.5 V
• Data Converters: A/D 14x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Processor Series: PIC16F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 256 B
• Interface Type: MSSP/EUSART
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 35
• 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, DM164120-2
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 14-ch x 10-bit
• Package: 44TQFP
• Device Core: PIC
• Family Name: PIC16
• Maximum Speed: 20 MHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: XLT44PT3 - SOCKET TRAN ICE 44MQFP/TQFPAC164305 - MODULE SKT FOR PM3 44TQFP444-1001 - DEMO BOARD FOR PICMICRO MCU
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

11.5.1
The PWM period is specified by the PR2 register of
Timer2. The PWM period can be calculated using the
formula of Equation 11-1.
EQUATION 11-1:
When TMR2 is equal to PR2, the following three events
occur on the next increment cycle:
• TMR2 is cleared
• The CCPx pin is set. (Exception: If the PWM duty
• The PWM duty cycle is latched from CCPRxL into
© 2007 Microchip Technology Inc.
cycle = 0%, the pin will not be set.)
CCPRxH.
Note:
PWM Period
PWM PERIOD
The Timer2 postscaler (see Section 7.1
“Timer2 Operation”) is not used in the
determination of the PWM frequency.
=
(TMR2 Prescale Value)
[
PWM PERIOD
(
PR2
)
+
1
] 4 T
•
•
OSC
•
PIC16F882/883/884/886/887
Preliminary
11.5.2
The PWM duty cycle is specified by writing a 10-bit
value to multiple registers: CCPRxL register and
DCxB<1:0> bits of the CCPxCON register. The
CCPRxL contains the eight MSbs and the DCxB<1:0>
bits of the CCPxCON register contain the two LSbs.
CCPRxL and DCxB<1:0> bits of the CCPxCON
register can be written to at any time. The duty cycle
value is not latched into CCPRxH until after the period
completes (i.e., a match between PR2 and TMR2
registers occurs). While using the PWM, the CCPRxH
register is read-only.
Equation 11-2 is used to calculate the PWM pulse
width.
Equation 11-3 is used to calculate the PWM duty cycle
ratio.
EQUATION 11-2:
EQUATION 11-3:
The CCPRxH register and a 2-bit internal latch are
used to double buffer the PWM duty cycle. This double
buffering is essential for glitchless PWM operation.
The 8-bit timer TMR2 register is concatenated with
either the 2-bit internal system clock (F
the prescaler, to create the 10-bit time base. The system
clock is used if the Timer2 prescaler is set to 1:1.
When the 10-bit time base matches the CCPRxH and
2-bit latch, then the CCPx pin is cleared (see
Figure 11-3).
Duty Cycle Ratio
Pulse Width
PWM DUTY CYCLE
=
(
T
=
CCPRxL:CCPxCON<5:4>
OSC
PULSE WIDTH
DUTY CYCLE RATIO
(
---------------------------------------------------------------------- -
CCPRxL:CCPxCON<5:4>
•
(TMR2 Prescale Value)
4 PR2
(
DS41291D-page 129
+
OSC
1
)
), or 2 bits of
)
•
)