204 Hardware Reference Manual
Intel® IXP2800 Network Processor
DRAM
The DRM Push Arbiter boundary conditions are:
Make sure each of the push_request queues assert the full signal and back pressure the
requesting unit.
Maintain 100% bus utilization, i.e., no holes.
5.12 DRAM Pull Arbiter Description
The general data flow for a push operation is as shown in Table69. The DRAM Pull Arbiter
functional blocks are shown in Figure 73.
The pull arbiter is very similar to the push arbiter, except that it gathers the data from a data source
ID and delivers it to the requesting unit where it is written to DRAM memory.
Figure 72. DRAM Push Arbiter Functional Blocks
A9732-01
D0_PUSH_REQ
DPXX_PUSH_ID
Round
Robin
A
R
B
I
T
E
R
D0_PUSH_ID
D1_PUSH_REQ
D1_PUSH_ID
D2_PUSH_REQ
D2_PUSH_ID
D0_PUSH_DATA
D1_PUSH_DATA
D2_PUSH_DATA
DPXX_PUSH_DATA
Table 69. DPLA Description
Pull Bus Master/Requestor Data Source Data Destination
IXP2800 Network Processor
D0 Unit
D1 Unit
D2 Unit
TC0 Cluster (Microengine 0 – 7)
TC1 Cluster (Microengine 8 – 15)
Intel XScale® core
PCI Unit
MSF Unit
Current Master