FW82801DBM S L6DN Intel, FW82801DBM S L6DN Datasheet - Page 178
![no-image](/images/manufacturer_photos/0/3/336/intel_sml.jpg)
FW82801DBM S L6DN
Manufacturer Part Number
FW82801DBM S L6DN
Description
Manufacturer
Intel
Datasheet
1.FW82801DBM_S_L6DN.pdf
(615 pages)
Specifications of FW82801DBM S L6DN
Lead Free Status / RoHS Status
Not Compliant
- Current page: 178 of 615
- Download datasheet (16Mb)
Functional Description
5.15.1.6
5.15.2
5.15.2.1
178
PIO IDE Data Port Prefetching and Posting
The ICH4 can be programmed via the IDETIM registers to allow data to be posted to and
prefetched from the IDE data ports. Data prefetching is initiated when a data port read occurs. The
read prefetch eliminates latency to the IDE data ports and allows them to be performed back to
back for the highest possible PIO data transfer rates. The first data port read of a sector is called the
demand read. Subsequent data port reads from the sector are called prefetch reads. The demand
read and all prefetch reads must be the same size (16 or 32 bits).
Data posting is performed for writes to the IDE data ports. The transaction is completed on the PCI
bus after the data is received by the ICH4. The ICH4 will then run the IDE cycle to transfer the data
to the drive. If the ICH4 write buffer is non-empty and an unrelated (non-data or opposite channel)
IDE transaction occurs, that transaction will be stalled until all current data in the write buffer is
transferred to the drive.
Bus Master Function
The ICH4 can act as a PCI Bus master on behalf of an IDE slave device. Two PCI Bus master
channels are provided, one channel for each IDE connector (primary and secondary). By
performing the IDE data transfer as a PCI Bus master, the ICH4 off-loads the processor and
improves system performance in multitasking environments. Both devices attached to a connector
can be programmed for bus master transfers, but only one device per connector can be active at a
time.
Physical Region Descriptor Format
The physical memory region to be transferred is described by a Physical Region Descriptor (PRD).
The PRDs are stored sequentially in a Descriptor Table in memory. The data transfer proceeds until
all regions described by the PRDs in the table have been transferred. Note that the ICH4 bus master
IDE function does not support memory regions or Descriptor tables located on ISA.
Descriptor Tables must not cross a 64-kB boundary. Each PRD entry in the table is 8 bytes in
length. The first 4 bytes specify the byte address of a physical memory region. This memory region
must be DWord aligned and must not cross a 64-kB boundary. The next two bytes specify the size
or transfer count of the region in bytes (64-kB limit per region). A value of zero in these two bytes
indicates 64 kB (thus, the minimum transfer count is 1). If bit 7 (EOT) of the last byte is a 1, it
indicates that this is the final PRD in the Descriptor table. Bus master operation terminates when
the last descriptor has been retired.
When the Bus Master IDE controller is reading data from the memory regions, bit 1 of the Base
Address is masked and byte enables are asserted for all read transfers. When writing data, bit 1 of
the Base Address is not masked and if set, causes the lower Word byte enables to be deasserted for
the first DWord transfer. The write to PCI typically consists of a 32-byte cache line. If valid data
ends prior to end of the cache line, the byte enables are deasserted for invalid data.
The total sum of the byte counts in every PRD of the descriptor table must be equal to or greater
than the size of the disk transfer request. If greater than the disk transfer request, the driver must
terminate the bus master transaction (by setting bit 0 in the Bus Master IDE Command Register to
0) when the drive issues an interrupt to signal transfer completion.
Intel
®
82801DBM ICH4-M Datasheet
Related parts for FW82801DBM S L6DN
Image
Part Number
Description
Manufacturer
Datasheet
Request
R
![FW82801DBM](/images/manufacturer_photos/0/3/337/intel_corporation_tmb.jpg)
Part Number:
Description:
I/O Controller Hub 4 Mobile
Manufacturer:
Intel Corporation
Datasheet:
![FW82801DB S L66K](/images/manufacturer_photos/0/3/336/intel_tmb.jpg)
Part Number:
Description:
Manufacturer:
Intel
Datasheet:
![FW82801DB S L6DM](/images/manufacturer_photos/0/3/336/intel_tmb.jpg)
Part Number:
Description:
Manufacturer:
Intel
Datasheet:
![RJ80535VC600512](/images/manufacturer_photos/0/3/337/intel_corporation_tmb.jpg)
Part Number:
Description:
Microprocessor: Intel Celeron M Processor 320 and Ultra Low Voltage Intel Celeron M Processor at 600MHz
Manufacturer:
Intel Corporation
![82550GY](/images/manufacturer_photos/0/3/337/intel_corporation_tmb.jpg)
Part Number:
Description:
Intel 82550 Fast Ethernet Multifunction PCI/CardBus Controller
Manufacturer:
Intel Corporation
Datasheet:
![DA28F320J5-120](/images/manufacturer_photos/0/3/337/intel_corporation_tmb.jpg)
Part Number:
Description:
Intel StrataFlash memory 32 Mbit. Access speed 120 ns
Manufacturer:
Intel Corporation
Datasheet:
![E28F320J5-120](/images/manufacturer_photos/0/3/337/intel_corporation_tmb.jpg)
Part Number:
Description:
Intel StrataFlash memory 32 Mbit. Access speed 120 ns
Manufacturer:
Intel Corporation
Datasheet:
![G28F640J5-150](/images/manufacturer_photos/0/3/337/intel_corporation_tmb.jpg)
Part Number:
Description:
Intel StrataFlash memory 64 Mbit. Access speed 150 ns
Manufacturer:
Intel Corporation
Datasheet:
![E28F320J5-100](/images/manufacturer_photos/0/3/337/intel_corporation_tmb.jpg)
Part Number:
Description:
Intel StrataFlash memory 32 Mbit. Access speed 100 ns
Manufacturer:
Intel Corporation
Datasheet:
![DA28F640J5A-150](/images/manufacturer_photos/0/3/337/intel_corporation_tmb.jpg)
Part Number:
Description:
DA28F640J5A-1505 Volt Intel StrataFlash Memory
Manufacturer:
Intel Corporation
Datasheet:
![DA28F320J5A-120](/images/manufacturer_photos/0/3/337/intel_corporation_tmb.jpg)
Part Number:
Description:
5 Volt Intel StrataFlash?? Memory
Manufacturer:
Intel Corporation
Datasheet:
![E28F320J5A-120](/images/manufacturer_photos/0/3/337/intel_corporation_tmb.jpg)
Part Number:
Description:
5 Volt Intel StrataFlash?? Memory
Manufacturer:
Intel Corporation
![NHE6300ESB](/images/manufacturer_photos/0/3/337/intel_corporation_tmb.jpg)
Part Number:
Description:
Intel 6300ESB I/O Controller Hub
Manufacturer:
Intel Corporation
Datasheet: