70592C Datasheet, PDF (155/314 Pages) Microchip Technology – High-Performance, 16-bit Microcontrollers

PIC24HJXXXGPX06A/X08A/X10A
14.0 INPUT CAPTURE
Note 1: This data sheet summarizes the features
of the PIC24HJXXXGPX06A/X08A/X10A
family of devices. However, it is not
intended to be a comprehensive refer-
ence source. To complement the infor-
mation in this data sheet, refer to the
“dsPIC33F/PIC24H Family Reference
Manual”, Section 12. “Input Capture”
(DS70248), which is available from the
Microchip website (www.microchip.com).
2: Some registers and associated bits
described in this section may not be
available on all devices. Refer to
Section 4.0 “Memory Organization” in
this data sheet for device-specific register
and bit information.
The input capture module is useful in applications
requiring frequency (period) and pulse measurement.
The PIC24HJXXXGPX06A/X08A/X10A devices
support up to eight 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 between 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
Sleep and Idle modes
• Interrupt on input capture event
• 4-word FIFO buffer for capture values
- Interrupt optionally generated after 1, 2, 3 or
4 buffer locations are filled
• Input capture can also be used to provide
additional sources of external interrupts.
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).
FIGURE 14-1:
INPUT CAPTURE BLOCK DIAGRAM
From 16-bit Timers
TMRy TMRz
ICx Pin
Prescaler
Counter
(1, 4, 16)
Edge Detection Logic
and
Clock Synchronizer
3
ICM<2:0> (ICxCON<2:0>)
Mode Select
ICOV, ICBNE (ICxCON<4:3>)
ICxI<1:0>
ICxCON
FIFO
R/W
Logic
Interrupt
Logic
16 ¹⁶
ICTMR
1
0 _(ICxCON<7>)
ICxBUF
System Bus
Set Flag ICxIF
(in IFSn Register)
Note: An ‘x’ in a signal, register or bit name denotes the number of the capture channel.
© 2011 Microchip Technology Inc.
DS70592C-page 155