Microchip Technology MA330031-2 Data Sheet
2011-2013 Microchip Technology Inc.
DS70000657H-page 375
dsPIC33EPXXXGP50X, dsPIC33EPXXXMC20X/50X AND PIC24EPXXXGP/MC20X
26.3
Programmable CRC Registers
REGISTER 26-1:
CRCCON1: CRC CONTROL REGISTER 1
R/W-0
U-0
R/W-0
R-0
R-0
R-0
R-0
R-0
CRCEN
—
CSIDL
VWORD4
VWORD3
VWORD2
VWORD1
VWORD0
bit 15
bit 8
R-0
R-1
R/W-0
R/W-0
R/W-0
U-0
U-0
U-0
CRCFUL
CRCMPT
CRCISEL
CRCGO
LENDIAN
—
—
—
bit 7
bit 0
Legend:
R = Readable 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
CRCEN:
CRC Enable bit
1
= CRC module is enabled
0
= CRC module is disabled; all state machines, pointers and CRCWDAT/CRCDAT are reset, other
SFRs are not reset
bit 14
Unimplemented:
Read as ‘0’
bit 13
CSIDL:
CRC Stop in Idle Mode bit
1
= Discontinues module operation when device enters Idle mode
0
= Continues 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<4:0> > 7
or 16 when PLEN<4:0>
or 16 when PLEN<4:0>
7.
bit 7
CRCFUL
: CRC FIFO Full bit
1
= FIFO is full
0
= FIFO is not full
bit 6
CRCMPT:
CRC FIFO Empty Bit
1
= FIFO is empty
0
= FIFO is not empty
bit 5
CRCISEL:
CRC Interrupt Selection bit
1
= Interrupt on FIFO is empty; final word of data is still shifting through CRC
0
= Interrupt on shift is complete and CRCWDAT results are ready
bit 4
CRCGO:
Start CRC bit
1
= Starts CRC serial shifter
0
= CRC serial shifter is turned off
bit 3
LENDIAN:
Data Word Little-Endian Configuration bit
1
= Data word is shifted into the CRC starting with the LSb (little endian)
0
= Data word is shifted into the CRC starting with the MSb (big endian)
bit 2-0
Unimplemented:
Read as ‘0’