Intel
®
81341 and 81342 I/O Processors
December 2007
Developer’s Manual
Order Number: 315037-002US
515
Application DMA Unit—Intel
®
81341 and 81342
5.12.1.2
Data Parity Generation
As a target during a memory-mapped register read access, the ADMA internal bus
interface generates and drives data parity when returning data for memory-mapped
register read requests.
As an initiator, the ADMA does
not
generate data parity. When receiving data from the
internal bus, the ADMA simply forwards the data and its parity to the DMCU as received
from the internal bus. When receiving data from the DMCU, the ADMA simply forwards
the data and its parity to the internal bus as received from the DMCU.
and
respectively list the address and data bytes that are used for
the address and data parity calculation. The parity bits are calculated by bit XORing the
data bits shown in
. As an example, the parity calculation for the lowest order
byte of the data bus D[7:0] is calculated as follows:
Equation 16.D_PARITY0 = D[0] XOR D[1] XOR D[2] XOR D[3] XOR D[4] XOR D[5] XOR
D[6] XOR D[7]
Table 311. Address Parity Checking/Generation
Address Parity Bit
Address Byte
A_PARITY4
A[35:32]
A_PARITY3
A[31:24]
A_PARITY2
A[23:16]
A_PARITY1
A[15:8]
A_PARITY0
A[7:0]
Table 312. Data Parity Checking/Generation
Data Parity Bit
Data Byte
Byte Enable
D_PARITY15
D[127:120]
BE15
D_PARITY14
D[119:112]
BE14
D_PARITY13
D[111:104]
BE13
D_PARITY12
D[103:96]
BE12
D_PARITY11
D[95:88]
BE11
D_PARITY10
D[87:80]
BE10
D_PARITY9
D[79:72]
BE9
D_PARITY8
D[71:64]
BE8
D_PARITY7
D[63:56]
BE7
D_PARITY6
D[55:48]
BE6
D_PARITY5
D[47:40]
BE5
D_PARITY4
D[39:32]
BE4
D_PARITY3
D[31:24]
BE3
D_PARITY2
D[23:16]
BE2
D_PARITY1
D[15:8]
BE1
D_PARITY0
D[7:0]
BE0