Intel
®
81341 and 81342—DDR SDRAM Memory Controller
Intel
®
81341 and 81342 I/O Processors
Developer’s Manual
December 2007
570
Order Number: 315037-002US
7.3.2
DMCU Arbitration and Configuration
The order transactions are processed by the DDR SDRAM Control block is determined by
the Memory Controller Arbiter (DMARB). The DMARB selects the next transaction from the
memory transaction queues and refresh control based on the settings programmed in the
DMARB configuration registers
“DMCU Port Transaction Count Register — DMPTCR” on
. These registers enable the DMCU to be tuned for optimal design performance.
7.3.2.1
DMCU Port Priority
The Memory controller for the 81341 and 81342 has six inbound ports for memory
transactions.
7.3.2.2
DMCU Port Transaction Count
The DMCU Port Transaction Count Register (DMPTCR) defines the number of
transactions the DMARB selects from a given port during the corresponding port
tenure. The intent is that ports with frequent small transactions (north internal bus
port) be allowed to complete multiple transactions during a tenure, while ports with
less frequent large transactions be limited to a small number of transactions (possibly
just 1).