
IDT DMA Controller
PES32NT24xG2 User Manual
15 - 9
January 30, 2013
Notes
The DMA channel performs the following actions as part of stride control DMA descriptor specific
processing.
–
The value in the Source Stride Size (SSSIZE) field in the descriptor is loaded into the Source
Stride Size (SSSIZE) field in the DMA Channel Stride Size (DMACxSSIZE) register.
–
The value in the Destination Stride Size (DSSIZE) field in the descriptor is loaded into the Desti-
nation Stride Size (DSSIZE) field in the DMACxSSIZE register.
–
The value of the Source Stride Distance (SSDIST) field in the descriptor is loaded into the Stride
Distance (SDIST) field in the DMA Channel Source Stride Control (DMACxSSCTL) register.
–
The value of the Source Stride Count (SSCOUNT) field is in the descriptor is loaded into the Stride
Count (SCOUNT) field in the DMACxSSCTL register.
–
The value of the Destination Stride Distance (DSDIST) field in the descriptor is loaded into the
Stride Distance (SDIST) field in the DMA Channel Destination Stride Control (DMACxDSCTL)
register.
–
The value of the Destination Stride Count (DSCOUNT) field is in the descriptor is loaded into the
Stride Count (SCOUNT) field in the DMACxDSCTL register.
Data Transfer Descriptor
A data transfer descriptor is used to instruct the DMA channel to transfer data from a source device to a
destination device. The format of a data transfer descriptor is shown in Figure 15.9 and the fields are
described in Table 15.5. Following the PCI convention, the format is shown in little-endian.
RRU
1
16
Request Rate Update. When this bit is set, the DMA channel
uses the value in the Request Rate (RR) field of this descriptor
to update the DMA Channel Request Rate Control (DMACxR-
RCTL) register.
SSDIST
2
15:0
Source Stride Distance. This field contains the source stride
distance in bytes. The value in this field is a signed number in
two’s complement notation.
SSCOUNT
2
31:16
Source Stride Count. This field contains the source stride
count. The value in this field is an unsigned number. This field
must be non-zero.
Reserved
3
31:0
Reserved.
DSDIST
4
15:0
Destination Stride Distance. This field contains the destination
stride distance in bytes. The value in this field is a signed num-
ber in two’s complement notation.
DSCOUNT
4
31:16
Destination Stride Count. This field contains the destination
count. The value in this field is an unsigned number. This field
must be non-zero.
Reserved
5
31:0
Reserved.
NEXTL
6
31:0
Next Descriptor Address Lower. Lower 32-bits of 64-bit next
descriptor DMA address. Descriptors must be word aligned thus
the lower two bits must be zero.
NEXTU
7
31:0
Next Descriptor Address Upper. Upper 32-bits of 64-bit next
descriptor DMA address.
SSSIZE
0
11:0
Source Stride Size. This field specifies the source stride in
bytes. A value of zero indicates an infinite stride size.
Field
DWord
Bit
Position
Description
Table 15.4 Stride Control DMA Descriptor Fields (Part 2 of 2)
Summary of Contents for PCI Express 89HPES32NT24xG2
Page 20: ...IDT Table of Contents PES32NT24xG2 User Manual x January 30 2013 Notes...
Page 24: ...IDT List of Tables PES32NT24xG2 User Manual xiv January 30 2013 Notes...
Page 28: ...IDT List of Figures PES32NT24xG2 User Manual xviii January 30 2013 Notes...
Page 56: ...IDT PES32NT24xG2 Device Overview PES32NT24xG2 User Manual 1 20 January 30 2013 Notes...
Page 100: ...IDT Switch Core PES32NT24xG2 User Manual 4 22 January 30 2013 Notes...
Page 128: ...IDT Failover PES32NT24xG2 User Manual 6 4 January 30 2013 Notes...
Page 148: ...IDT Link Operation PES32NT24xG2 User Manual 7 20 January 30 2013 Notes...
Page 164: ...IDT SerDes PES32NT24xG2 User Manual 8 16 January 30 2013 Notes...
Page 170: ...IDT Power Management PES32NT24xG2 User Manual 9 6 January 30 2013 Notes...
Page 196: ...IDT Transparent Switch Operation PES32NT24xG2 User Manual 10 26 January 30 2013 Notes...
Page 244: ...IDT SMBus Interfaces PES32NT24xG2 User Manual 12 40 January 30 2013 Notes...
Page 247: ...IDT General Purpose I O PES32NT24xG2 User Manual 13 3 January 30 2013 Notes...
Page 248: ...IDT General Purpose I O PES32NT24xG2 User Manual 13 4 January 30 2013 Notes...
Page 330: ...IDT Switch Events PES32NT24xG2 User Manual 16 6 January 30 2013 Notes...
Page 342: ...IDT Multicast PES32NT24xG2 User Manual 17 12 January 30 2013 Notes...
Page 344: ...IDT Temperature Sensor PES32NT24xG2 User Manual 18 2 January 30 2013 Notes...
Page 384: ...IDT Register Organization PES32NT24xG2 User Manual 19 40 January 30 2013...
Page 492: ...IDT Proprietary Port Specific Registers PES32NT24xG2 User Manual 21 44 January 30 2013 Notes...
Page 588: ...IDT NT Endpoint Registers PES32NT24xG2 User Manual 22 96 January 30 2013 Notes...
Page 710: ...IDT JTAG Boundary Scan PES32NT24xG2 User Manual 25 12 January 30 2013 Notes...
Page 743: ...IDT Usage Models PES32NT24xG2 User Manual 26 33 January 30 2013 Notes...
Page 744: ...IDT Usage Models PES32NT24xG2 User Manual 26 34 January 30 2013 Notes...