Microchip Technology MA240017 Scheda Tecnica
2008-2011 Microchip Technology Inc.
DS39927C-page 169
PIC24F16KA102 FAMILY
20.3
Registers
There are four registers used to control programmable
CRC operation:
• CRCCON
• CRCXOR
• CRCDAT
• CRCWDAT
CRC operation:
• CRCCON
• CRCXOR
• CRCDAT
• CRCWDAT
REGISTER 20-1:
CRCCON: CRC CONTROL REGISTER
U-0
U-0
R/W-0
R-0, HSC
R-0, HSC
R-0, HSC
R-0, HSC
R-0, HSC
—
—
CSIDL
VWORD4
VWORD3
VWORD2
VWORD1
VWORD0
bit 15
bit 8
R-0, HSC
R-1, HSC
U-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
CRCFUL
CRCMPT
—
CRCGO
PLEN3
PLEN2
PLEN1
PLEN0
bit 7
bit 0
Legend:
HSC = Hardware Settable/Clearable bit
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
bit 15-14
Unimplemented:
Read as ‘0’
bit 13
CSIDL:
CRC Stop in Idle Mode bit
1
= Discontinue module operation when device enters Idle mode
0
= Continue module operation in Idle mode
bit 12-8
VWORD<4:0>:
Pointer Value bits
Indicates the number of valid words in the FIFO. Has a maximum value of 8 when PLEN<3:0> > 7, or
16 when PLEN<3:0>
16 when PLEN<3:0>
7.
bit 7
CRCFUL
: FIFO Full bit
1
= FIFO is full
0
= FIFO is not full
bit 6
CRCMPT:
FIFO Empty Bit
1
= FIFO is empty
0
= FIFO is not empty
bit 5
Unimplemented:
Read as ‘0’
bit 4
CRCGO:
Start CRC bit
1
= Start CRC serial shifter
0
= CRC serial shifter is turned off
bit 3-0
PLEN<3:0>:
Polynomial Length bits
Denotes the length of the polynomial to be generated minus 1.