1Gb DDR3L – AS4C128M8D3L
- Multi-Purpose Register (MPR)
The Multi Purpose Register (MPR) function is used to Read out a predefined system timing calibration bit sequence.
Figure 8. MPR Block Diagram
Memory Core
(all banks precharged)
MRS 3
【A2】
Multipurpose register
Pre-defined data for Reads
DQ, DM, DQS, DQS#
To enable the MPR, a MODE Register Set (MRS) command must be issued to MR3 Register with bit A2 = 1. Prior to
issuing the MRS command, all banks must be in the idle state (all banks precharged and tRP met). Once the MPR is
enabled, any subsequent RD or RDA commands will be redirected to the Multi Purpose Register. The resulting
operation, when a RD or RDA command is issued, is defined by MR3 bits A[1:0] when the MPR is enabled as shown
in table 11. When the MPR is enabled, only RD or RDA commands are allowed until a subsequent MRS command is
issued with the MPR disabled (MR3 bit A2 = 0). Note that in MPR mode RDA has the same functionality as a READ
command which means the auto precharge part of RDA is ignored. Power-Down mode, Self-Refresh and any other
non-RD/RDA command is not allowed during MPR enable mode. The RESET function is supported during MPR
enable mode.
Table 19. MPR MR3 Register Definition
MR3 A[2]
MR3 A[1:0]
Function
MPR
MPR-Loc
Normal operation, no MPR transaction.
0b
1b
Don’t care (0b or 1b) All subsequent Reads will come from DRAM array.
All subsequent Write will go to DRAM array.
Enable MPR mode, subsequent RD/RDA commands defined by
See the table11
MR3 A[1:0].
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Rev. 2.0
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ALSC [ ALLIANCE SEMICONDUCTOR CORPORATION ]
