PIC32MX1XX_12 Datasheet, PDF (106/328 Pages) Microchip Technology – 32-bit Microcontrollers (up to 128 KB Flash and 32 KB SRAM) with Audio and Graphics Interfaces, USB, and Advanced Analog

PIC32MX1XX/2XX
REGISTER 9-4: DCRCCON: DMA CRC CONTROL REGISTER
Bit
Bit
Bit
Bit
Bit
Bit
Bit
Bit
Bit
Range 31/23/15/7 30/22/14/6 29/21/13/5 28/20/12/4 27/19/11/3 26/18/10/2 25/17/9/1 24/16/8/0
31:24
23:16
15:8
7:0
U-0
—
U-0
—
U-0
—
R/W-0
CRCEN
U-0
—
U-0
—
U-0
—
R/W-0
CRCAPP⁽¹⁾
R/W-0
R/W-0
BYTO<1:0>
U-0
U-0
—
—
U-0
R/W-0
—
R/W-0
U-0
CRCTYP
—
R/W-0
WBO⁽¹⁾
U-0
—
R/W-0
U-0
—
U-0
U-0
—
—
U-0
U-0
—
—
R/W-0
PLEN<4:0>
R/W-0
R/W-0
R/W-0
CRCCH<2:0>
R/W-0
BITO
U-0
—
R/W-0
R/W-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 31-30 Unimplemented: Read as ‘0’
bit 29-28 BYTO<1:0>: CRC Byte Order Selection bits
11 = Endian byte swap on half-word boundaries (i.e., source half-word order with reverse source byte order
per half-word)
10 = Swap half-words on word boundaries (i.e., reverse source half-word order with source byte order per
half-word)
01 = Endian byte swap on word boundaries (i.e., reverse source byte order)
00 = No swapping (i.e., source byte order)
bit 27 WBO: CRC Write Byte Order Selection bit⁽¹⁾
1 = Source data is written to the destination re-ordered as defined by BYTO<1:0>
0 = Source data is written to the destination unaltered
bit 26-25 Unimplemented: Read as ‘0’
bit 24 BITO: CRC Bit Order Selection bit
When CRCTYP (DCRCCON<15>) = 1 (CRC module is in IP Header mode):
1 = The IP header checksum is calculated Least Significant bit (LSb) first (i.e., reflected)
0 = The IP header checksum is calculated Most Significant bit (MSb) first (i.e., not reflected)
When CRCTYP (DCRCCON<15>) = 0 (CRC module is in LFSR mode):
1 = The LFSR CRC is calculated Least Significant bit first (i.e., reflected)
0 = The LFSR CRC is calculated Most Significant bit first (i.e., not reflected)
bit 23-13 Unimplemented: Read as ‘0’
bit 12-8 PLEN<4:0>: Polynomial Length bits
When CRCTYP (DCRCCON<15>) = 1 (CRC module is in IP Header mode):
These bits are unused.
When CRCTYP (DCRCCON<15>) = 0 (CRC module is in LFSR mode):
Denotes the length of the polynomial – 1.
bit 7
CRCEN: CRC Enable bit
1 = CRC module is enabled and channel transfers are routed through the CRC module
0 = CRC module is disabled and channel transfers proceed normally
Note 1: When WBO = 1, unaligned transfers are not supported and the CRCAPP bit cannot be set.
DS61168E-page 106
Preliminary
 2011-2012 Microchip Technology Inc.