Intel
®
81341 and 81342 I/O Processors
December 2007
Developer’s Manual
Order Number: 315037-002US
477
Application DMA Unit—Intel
®
81341 and 81342
Each word in the Dual XOR chain descriptor is analogous to control register values. A
chain descriptor is interpreted as a Dual XOR operation when bit 17 of the second word
in the descriptor is set; note that this is analogous to bit 17 of the
Control Register x — ADCRx” on page 526
.
• First word is the local memory address of the next chain descriptor. A value of zero
specifies the end of the chain. This value is loaded into the ADMA Next Descriptor
Address Register. Because basic chain descriptors must be aligned on an 8-word
boundary, the unit may ignore bits 04:00 of this address.
• Second word is the Descriptor Control Word. This word configures Application DMA
for one operation. This value is loaded into the ADMA Descriptor Control Register.
• Third word is Reserved and must be written with 0000 0000H.
• Fourth word contains the 24-bit, Byte Count value. This value specifies the number
of bytes of data in the current chain descriptor. Also, the upper byte of this word is
the Transfer Status field that may be written back to the Byte Count Word at the
end of the ADMA transfer when the Status Write Back Enable in the ADCR is set.
This value is loaded into the ADMA Byte Count Register.
• Fifth word is the lower 32-bit Horizontal destination address. The ADMA uses this
value for the lower 32-bits of the Horizontal destination address for the Dual-XOR-
transfer operation. This value is loaded into the Destination Lower Address Register.
• Sixth word is the upper 32-bit Horizontal destination address. The ADMA uses this
value for the upper 32-bits of the Horizontal destination address for the Dual-XOR-
transfer operation. This value is loaded into the Destination Upper Address Register.
• Seventh word is lower 32-bit source address for first data block of the Dual-XOR-
transfer operation. This value is loaded into the Source Lower Address Register 0.
• Eighth word is upper 32-bit source address for the first data block of the Dual-XOR-
transfer operation. This value is loaded into the Source Upper Address Register 0.
• Ninth word is lower 32-bit source address for the second data block of the Dual-
XOR-transfer operation. This value is loaded into the Source Lower Address
Register 1.
• Tenth word is upper 32-bit source address for the second data block of the Dual-
XOR-transfer operation. This value is loaded into the Source Upper Address
Register 1.
• Eleventh word is lower 32-bit source address for Horizontal source of the Dual-
XOR-transfer operation. This value is loaded into the Source Lower Address
Register 2.
• Twelfth word is upper 32-bit source address for the Horizontal source of the Dual-
XOR-transfer operation. This value is loaded into the Source Upper Address
Register 2.
• Thirteenth word is lower 32-bit source address for Diagonal source of the Dual-
XOR-transfer operation. This value is loaded into the Source Lower Address
Register 3.
• Fourteenth word is upper 32-bit source address for the Diagonal source of the
Dual-XOR-transfer operation. This value is loaded into the Source Upper Address
Register 3.
• Fifteenth word is lower 32-bit destination address for the Diagonal destination of
the Dual-XOR-transfer operation. This value is loaded into the Source Lower
Address Register 4.
• Sixteenth word is upper 32-bit destination address for the Diagonal destination of
the Dual-XOR-transfer operation. This value is loaded into the Source Upper
Address Register 4.