PIC24HJ12GP201 Datasheet, PDF (119/234 Pages) Microchip Technology – High-Performance, 16-Bit Microcontrollers

PIC24HJ12GP201/202
12.0 INPUT CAPTURE
Note:
This data sheet summarizes the features
of the PIC24HJ12GP201/202 devices. It is
not intended to be a comprehensive
reference source. To complement the
information in this data sheet, refer to the
“PIC24H Family Reference Manual”.
Please see the Microchip web site
(www.microchip.com) for the latest
PIC24H Family Reference Manual
chapters.
The input capture module is useful in applications
requiring frequency (period) and pulse measurement.
The PIC24HJ12GP201/202 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 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
• Use of input capture to provide additional sources
of external interrupts
FIGURE 12-1:
INPUT CAPTURE BLOCK DIAGRAM
From 16-bit Timers
TMR2 TMR3
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
1
0
ICTMR
(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.
© 2007 Microchip Technology Inc.
Preliminary
DS70282B-page 117