Altera DDR SDRAM High-Performance Controllers and ALTMEMP Manuel d'utilisateur Page 83

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Chapter 5: Functional Description—ALTMEMPHY 5–37
PHY-to-Controller Interfaces
June 2011 Altera Corporation External Memory Interface Handbook Volume 3
Section I. DDR and DDR2 SDRAM Controllers with ALTMEMPHY IP User Guide
Figure 5–15 shows full-rate reads; Figure 5–16 shows half-rate reads.
Figure 5–17 and Figure 5–18 show word-aligned writes and reads. In the following
read and write examples the data is written to and read from the same address. In
each example,
ctl_rdata
and
ctl_wdata
are aligned with controller clock (
ctl_clk
)
cycles. All the data in the bit vector is valid at once. For comparison, refer Figure 5–19
and Figure 5–20 that show the word-unaligned writes and reads.
Figure 5–15. Full-Rate Reads
Figure 5–16. Half-Rate Reads
ctl_rlat = 9
12 3 4 56 7 8 9
clock
ctl_addr
ctl_cs_n
ctl_doing_rd
mem_dqs
mem_dq
ctl_rdata_valid
ctl_rdata
clock
ctl_addr
ctl_cs_n
ctl_doing_rd
mem_dqs
mem_dq
ctl_rdata_valid
ctl_rdata
AX XA
10
10 01
10 01
DX XD
ctl_rlat = 9
12 3 4 56 7 8 9
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