BCM1250/BCM1125/BCM1125H
User Manual
10/21/02
B r o a d c o m C o r p o r a t i o n
Page
186
Section 7: DMA
Document
1250_1125-UM100CB-R
Table 119: Data Mover CRC/Checksum Definition Registers (Only if System Revision >= PERIPH_REV3)
ctcp_def_0 -
00_1002_0B88
ctcp_def_1 -
00_1002_0B98
Bits
Name
Default
Description
31:0
crc_txor
32'bx
This value is XORed with the partial result of the CRC computation before the final result
is written to memory. For CRCs smaller than 32 bits the value should be put into the high
bits of this field and the low bits should be zeros.
47:32
tcpcs_init
16'bx
This is the initial value for the checksum and is loaded into the partial result register
before a move that has the tcpcs_reset flag set.
49:48
crc_width
2'bx
This sets the field width used when the CRC is written to memory:
00 - 4 bytes (32 bits)
01 - 2 bytes (16 bits)
10 - 1 byte (8 bits)
11 - Reserved
50
crc_bit_order
1'bx
This selects the bit order used when the CRC engine is reading bytes.
0 - Bit 0 is used first and bit 7 last
1 - Bit 7 is used first and bit 0 last
63:51 reserved 13'bx
Reserved.
Table 120: Data Mover Channel Partial Result Registers (Only if System Revision >= PERIPH_REV3)
dm_partial_0 -
00_1002_0BA0
dm_partial_1 -
00_1002_0BA8
dm_partial_2 -
00_1002_0BB0
dm_partial_3 -
00_1002_0BB8
Bits
Name
Default
Description
31:0
crc_partial
32'bx
Current partial CRC result. After a transfer with the crc_ap append bit set this register
will contain the final CRC result (after XOR and bit-flip). For CRCs smaller than 32 bits
the value is in the high bits of this field. If the value is saved it may be written back later
to allow the CRC computation to resume.
47:32 tcpcs_partial
16'bx
Current checksum partial result. If the value of this field and the odd_byte bit are saved
they may be written back later to allow the checksum computation to resume.
48
odd_byte
1'bx
This bit is set when the current checksum finished on an odd byte boundary. Since the
checksum is calculated in 16 bit halfwords this bit being set indicates that the first byte
of the next buffer must be added to the low half of the partial result before 16 bit additions
are used. If the value of this bit and the tcpcs_partial field are saved they may be written
back later to allow the checksum computation to resume.
63:49 reserved 15'bx
Reserved.