PIC18F2331/2431/4331/4431
The three input capture channels are controlled
through the Input Capture Control registers,
CAP1CON, CAP2CON and CAP3CON. Each channel
is configured independently with its dedicated register.
The implementation of the registers is identical except
for the Special Event Trigger (see Section 17.1.8
“Special Event Trigger (CAP1 Only)”). The typical
Capture Control register is shown in Register 17-1.
Note:
Throughout this section, references to
registers and bit names that may be asso-
ciated with a specific capture channel will
be referred to generically by the use of the
term ‘x’ in place of the channel number.
For example, ‘CAPxREN’ may refer to the
Capture Reset Enable bit in CAP1CON,
CAP2CON or CAP3CON.
REGISTER 17-1: CAPxCON: INPUT CAPTURE x CONTROL REGISTER
U-0
—
R/W-0
U-0
—
U-0
—
R/W-0
R/W-0
R/W-0
R/W-0
CAPxREN
CAPxM3
CAPxM2
CAPxM1
CAPxM0
bit 7
bit 0
Legend:
R = Readable bit
-n = Value at POR
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared x = Bit is unknown
bit 7
bit 6
Unimplemented: Read as ‘0’
CAPxREN: Time Base Reset Enable bit
1= Enabled
0= Disable selected time base Reset on capture
bit 5-4
bit 3-0
Unimplemented: Read as ‘0’
CAPxM<3:0>: Input Capture x (ICx) Mode Select bits
1111= Special Event Trigger mode; the trigger occurs on every rising edge on CAP1 input(1)
1110= Special Event Trigger mode; the trigger occurs on every falling edge on CAP1 input(1)
1101= Unused
1100= Unused
1011= Unused
1010= Unused
1001= Unused
1000= Capture on every CAPx input state change
0111= Pulse-Width Measurement mode, every rising to falling edge
0110= Pulse-Width Measurement mode, every falling to rising edge
0101= Frequency Measurement mode, every rising edge
0100= Capture mode, every 16th rising edge
0011= Capture mode, every 4th rising edge
0010= Capture mode, every rising edge
0001= Capture mode, every falling edge
0000= Input Capture x (ICx) off
Note 1: Special Event Trigger is only available on CAP1. For CAP2 and CAP3, this configuration is unused.
2010 Microchip Technology Inc.
DS39616D-page 155
MICROCHIP [ MICROCHIP ]
