EP80579 Datasheet, PDF (763/1916 Pages) Intel Corporation – Intel® EP80579 Integrated Processor Product Line

Intel^® EP80579 Integrated Processor
20.0 LPC DMA
20.1
Overview
LPC DMA is supported using the IICH DMA controller. The DMA controller has registers
that are fixed in the lower 64 Kbyte of I/O space. The DMA controller is configured
using registers in the PCI configuration space. These registers allow configuration of
the channels for use by LPC DMA.
The DMA circuitry incorporates the functionality of two 8237 DMA controllers with
seven independently programmable channels; Channels 0–3 and Channels 5–7. DMA
Channel 4 cascades the two controllers together and is not available for other use.
In addition to accepting requests from DMA slaves, the DMA controller also responds to
requests that software initiates. Software may initiate a DMA service request by setting
any bit in the DMA Channel Request Register to a one. The DMA controller is used for
LPC DMA.
Figure 20-1. IICH DMA Controller
Channel 0
Channel 1
Channel 2
Channel 3
DMA-1
Channel 4
Channel 5
Channel 6
Channel 7
DMA-2
Feature set of the IICH DMA controller:
• Channels 0–3 provide 8-bit, count-by-bytes transfers.
• Channels 5–7 provide 16-bit, count-by-words transfers.
• 24-bit addressing. Each channel includes a 16-bit, legacy-compatible Current
Address Register (CAR), which holds the 16 least-significant bits, and an legacy
Compatible Page Register, which contains the eight next most significant bits of
address.
• Auto-initialization following a DMA termination.
The DMA controller has registers that are fixed in the lower 64 Kbyte of I/O space.
The DMA controller is configured using registers in the PCI configuration space. These
registers allow configuration of individual channels for use by LPC.
The RPR bit effects the register decoding for the Reserved Page register (Addresses 80,
84-86, 88, 8C-8E and their aliases in the 9x range). See Section 17.1.6.3, “Offset
3410h: GCS: General Control and Status Register”bit 2.
August 2009
Order Number: 320066-003US
Intel^® EP80579 Integrated Processor Product Line Datasheet
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