NH82801HBM S LB9A Intel, NH82801HBM S LB9A Datasheet - Page 129

• Manufacturer Part Number: NH82801HBM S LB9A
• Description: CONTROLLER HUB, ICH8M, I/O, 82801HBM
• Manufacturer: Intel

Specifications of NH82801HBM S LB9A

• Power Dissipation Pd: 2.4W
• Digital Ic Case Style: BGA
• No. Of Pins: 676
• Pci Bus Type: I/O Controller Hub
• Pci Express Base Spec: PCIe 1.1
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Functional Description
5.5
Figure 8.
5.5.1
Intel
®
ICH8 Family Datasheet
Bus Master Device Mapping and START Fields
Bus Masters must have a unique START field. In the case of the ICH8 that supports two
LPC bus masters, it drives 0010 for the START field for grants to bus master #0
(requested via LDRQ0#) and 0011 for grants to bus master #1 (requested via
LDRQ1#.). Thus, no registers are needed to configure the START fields for a particular
bus master.
DMA Operation (D31:F0)
The ICH8 supports LPC DMA using the ICH8’s DMA controller. The DMA controller has
registers that are fixed in the lower 64 KB 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 82C37 DMA controllers with
seven independently programmable channels
corresponds to DMA channels 0–3 and DMA controller 2 (DMA-2) corresponds to
channels 5–7. DMA channel 4 is used to cascade the two controllers and defaults to
cascade mode in the DMA Channel Mode (DCM) Register. Channel 4 is not available for
any other purpose. 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 1.
Intel
Each DMA channel is hardwired to the compatible settings for DMA device size:
channels [3:0] are hardwired to 8-bit, count-by-bytes transfers, and channels [7:5] are
hardwired to 16-bit,
count-by-words (address shifted) transfers.
ICH8 provides 24-bit addressing in compliance with the ISA-Compatible specification.
Each channel includes a 16-bit ISA-Compatible Current Register which holds the 16
least-significant bits of the 24-bit address, an ISA-Compatible Page Register which
contains the eight next most significant bits of address.
The DMA controller also features refresh address generation, and auto-initialization
following a DMA termination.
Channel Priority
For priority resolution, the DMA consists of two logical channel groups: channels 0–3
and channels 4–7. Each group may be in either fixed or rotate mode, as determined by
the DMA Command Register.
DMA I/O slaves normally assert their DREQ line to arbitrate for DMA service. However,
a software request for DMA service can be presented through each channel's DMA
Request Register. A software request is subject to the same prioritization as any
hardware request. See the detailed register description for Request Register
programming information in
®
ICH8 DMA Controller
Channel 1
Channel 2
Channel 3
Channel 0
Section
DMA-1
9.2.
Channel 4
Channel 5
Channel 6
Channel 7
(Figure
8). DMA controller 1 (DMA-1)
DMA-2
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