User guide

9–2 Chapter 9: Timing Diagrams
DDR3 High-Performance Controllers
External Memory Interface Handbook Volume 3 December 2010 Altera Corporation
Section II. DDR3 SDRAM Controller with ALTMEMPHY IP User Guide
Auto-Precharge
The auto-precharge read and auto-precharge write commands allow you to indicate
to the memory device that this read or write command is the last access to the
currently open row. The memory device automatically closes (auto-precharges) the
page it is currently accessing so that the next access to the same bank is quicker. This
command is particularly useful for applications that require fast random accesses.
Figure 9–1. Auto-Precharge Operation for HPC
Notes to Figure 9–1:
(1) The auto-precharge request goes high.
(2) The
local_ready signal is asserted and remains high until the auto-precharge request goes low.
(3) A new row address begins.
phy_clk
local_autopch_req
Local Interface
local_ready
local_write_req
local_read_req
local_row_addr[13:0]
local_col_addr[9:0]
local_bank_addr[2:0]
mem_local_addr[24:0]
Memory Command[2:0]
AFI Memory Interface
mem_addr[13:0]
mem_clk
mem_clk_n
mem_cs_n
mem_dq[7:0]
mem_dqs
mem_dqsn
0002
0003
004 008
00C
010 000 004 008
00C
010
000
0C00100
0C00200
NOP WR NOP WR NOP
NOP
WR
0003 0000 0004 0008 000C 0410 0000 0004 0008 000C
0410
00 00
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