cx82100 Conexant Systems, Inc., cx82100 Datasheet - Page 66

• Manufacturer Part Number: cx82100
• Description: Home Network Processor Hnp
• Manufacturer: Conexant Systems, Inc.

4.6
4.6.1
4.6.2
4-6
Three Basic Modes of Address Generation
Source or Destination Mode
Circular Buffer Modes
Conexant Proprietary and Confidential Information
DMAC_{x}_Ptr1 is initialized by the microcontroller to point to the beginning of a
dword-aligned source or destination buffer. This pointer advances (by 1 qword) after
each transfer request X{x}R. Reading this pointer returns the current qword location to
be handled next by the DMAC when it processes the channel request.
Two circular buffer modes are supported:
•
•
Direct Circular Buffer
Figure 4-1 depicts how the addresses are generated in the Direct Circular Buffer mode.
Figure 4-1. Address Generation in Direct Circular Buffer Mode
The direct circular buffer for the downstream USB receive data channels.
The indirect circular pointer table for the Ethernet receive channels.
CX82100 Home Network Processor Data Sheet
(Fixed)
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8 Bytes
Bottom
To p
∆ ∆ ∆ ∆
∆
=
DM AC_{x}_C nt1
DM AC_{x}_C nt2 -
Current P ointer
Base P ointer
D M AC_{x}_Cnt1
DM AC_{x}_Ptr2
DM AC_{x}_Ptr1
8*
-1
+
∆ ∆ ∆ ∆
(Fixed)
101306C
101545_010