PIC16F818-I/P Microchip Technology, PIC16F818-I/P Datasheet - Page 206

• Manufacturer Part Number: PIC16F818-I/P
• Description: IC MCU FLASH 1KX14 18-DIP
• Manufacturer: Microchip Technology
• Series: PIC® 16Fr

Specifications of PIC16F818-I/P

• Program Memory Type: FLASH
• Program Memory Size: 1.75KB (1K x 14)
• Package / Case: 18-DIP (0.300", 7.62mm)
• Core Processor: PIC
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: I²C, SPI
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 16
• Eeprom Size: 128 x 8
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 5.5 V
• Data Converters: A/D 5x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Processor Series: PIC16F
• Core: PIC
• Data Bus Width: 8 bit
• Data Ram Size: 128 B
• Interface Type: I2C/SPI/SSP
• 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: Through Hole
• 3rd Party Development Tools: 52715-96, 52716-328, 52717-734
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120, ICE2000, DM163014
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 5-ch x 10-bit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: ACICE0202 - ADAPTER MPLABICE 18P 300 MILAC164010 - MODULE SKT PROMATEII DIP/SOIC
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

PICmicro MID-RANGE MCU FAMILY
14.3
14.3.1
DS31014A-page 14-4
CCP Pin Configuration
Capture Mode
In Capture mode, CCPRxH:CCPRxL captures the 16-bit value of the TMR1 register when an
event occurs on pin CCPx. An event is defined as:
• Every falling edge
• Every rising edge
• Every 4th rising edge
• Every 16th rising edge
An event is selected by control bits CCPxM3:CCPxM0 (CCPxCON<3:0>). When a capture is
made, the interrupt request flag bit, CCPxIF, is set. The CCPxIF bit must be cleared in software.
If another capture occurs before the value in register CCPRx is read, the previous captured value
will be lost.
As can be seen in
Timer1 can also be used as the timebase for other operations. The time between two captures
can easily be computed as the difference between the value of the second capture that of the
first capture. When Timer1 overflows, the TMR1IF bit will be set and if enabled an interrupt will
occur, allowing the time base to be extended to greater than 16-bits.
In Capture mode, the CCPx pin should be configured as an input by setting its corresponding
TRIS bit.
Figure 14-1: Capture Mode Operation Block Diagram
The prescaler can be used to get a very fine average resolution on a constant input frequency.
For example, if we have a stable input frequency and we set the prescaler to 1:16, then the total
error for those 16 periods is 1 T
is 12.5 ns. This technique is only valid where the input frequency is “stable” over the 16 samples.
Without using the prescaler (1:1), each sample would have a resolution of T
Note:
Note:
Timer1 must be running in timer mode or synchronized counter mode for the CCP
module to use the capture feature. In asynchronous counter mode, the capture
operation may not work.
If the CCPx pin is configured as an output, a write to the port can cause a capture
condition.
CCPx Pin
Figure
14-1, a capture does not reset the 16-bit TMR1 register. This is so
edge detect
Q’s
Prescaler
CY
1, 4, 16
and
. This gives an effective resolution of T
CCPxCON<3:0>
Set flag bit CCPxIF
Capture
Enable
CCPRxH
TMR1H
1997 Microchip Technology Inc.
CCPRxL
TMR1L
CY
/16, which at 20 MHz
CY
.