Microchip Technology MA330019 Data Sheet
© 2007-2012 Microchip Technology Inc.
DS70291G-page 205
dsPIC33FJ32MC302/304, dsPIC33FJ64MCX02/X04 AND dsPIC33FJ128MCX02/X04
14.0 INPUT CAPTURE
The Input Capture module is useful in applications that
requires frequency (period) and pulse measurement.
The dsPIC33FJ32MC302/304, dsPIC33FJ64MCX02/
X04 and dsPIC33FJ128MCX02/X04 devices support
up to four input capture channels.
The input capture module captures the 16-bit value of
the selected Time Base register when an event occurs
at the ICx pin. The events that cause a capture event
are listed below in three categories:
requires frequency (period) and pulse measurement.
The dsPIC33FJ32MC302/304, dsPIC33FJ64MCX02/
X04 and dsPIC33FJ128MCX02/X04 devices support
up to four input capture channels.
The input capture module captures the 16-bit value of
the selected Time Base register when an event occurs
at the ICx pin. The events that cause a capture event
are listed below in three categories:
• Simple Capture Event modes:
- Capture timer value on every falling edge of
input at ICx pin
- Capture timer value on every rising edge of
input at ICx pin
• Capture timer value on every edge (rising and
falling)
• Prescaler Capture Event modes:
- Capture timer value on every 4th rising
edge of input at ICx pin
- Capture timer value on every 16th rising
edge of input at ICx pin
Each input capture channel can select one of two 16-bit
timers (Timer2 or Timer3) for the time base. The
selected timer can use either an internal or external
clock.
Other operational features include:
• Device wake-up from capture pin during CPU
timers (Timer2 or Timer3) for the time base. The
selected timer can use either an internal or external
clock.
Other operational features include:
• Device wake-up from capture pin during CPU
Sleep and Idle modes
• Interrupt on input capture event
• 4-word FIFO buffer for capture values
• 4-word FIFO buffer for capture values
- Interrupt optionally generated after 1, 2, 3 or
4 buffer locations are filled
• Use of input capture to provide additional sources
of external interrupts
FIGURE 14-1:
INPUT CAPTURE BLOCK DIAGRAM
Note 1: This data sheet summarizes the features
of the dsPIC33FJ32MC302/304,
dsPIC33FJ64MCX02/X04 and
dsPIC33FJ128MCX02/X04 family of
devices. It is not intended to be a
comprehensive reference source. To
complement the information in this data
sheet, refer to Section 12. “Input
Capture” (DS70198) of the “dsPIC33F/
PIC24H Family Reference Manual”,
which is available from the Microchip web
site (
dsPIC33FJ64MCX02/X04 and
dsPIC33FJ128MCX02/X04 family of
devices. It is not intended to be a
comprehensive reference source. To
complement the information in this data
sheet, refer to Section 12. “Input
Capture” (DS70198) of the “dsPIC33F/
PIC24H Family Reference Manual”,
which is available from the Microchip web
site (
www.microchip.com
).
2: Some registers and associated bits
described in this section may not be
available on all devices. Refer to
available on all devices. Refer to
in
this data sheet for device-specific register
and bit information.
and bit information.
Note:
Only IC1 and IC2 can trigger a DMA data
transfer. If DMA data transfers are
required, the FIFO buffer size must be set
to ‘1’ (ICI<1:0> = 00)
transfer. If DMA data transfers are
required, the FIFO buffer size must be set
to ‘1’ (ICI<1:0> = 00)
Note: An ‘x’ in a signal, register or bit name denotes the number of the capture channel.
FIFO CONTROL
ICxBUF
TMR2 TMR3
CaptureEvent
/N
FIFO
ICI<1:0>
ICM<2:0>
ICM<2:0>
101
100
011
010
001
001
111
111
To CPU
Set Flag ICxIF
(In IFSx Register)
Rising Edge Mode
Prescaler Mode
(4th Rising Edge)
Falling Edge Mode
Edge Detection
Prescaler Mode
(16th Rising Edge)
Sleep/Idle
Wake-up Mode
ICTMR
ICx pin
Mode