Altera QDRII SRAM Controller MegaCore Function - Manual (Page 48)

3–16 MegaCore Version 9.1 Altera Corporation
QDRII SRAM Controller MegaCore Function User Guide November 2009
Interfaces & Signals
Figure 3–12. Isolated Read—Burst of Four (Narrow Mode)
Figure 3–13 shows a single read request from the Avalon interface for a
burst of two. The principle is identical to the burst of four, but all the data
bits coming back are transferred onto the Avalon interface. The timing on
the QDRII SRAM interface is slightly different as the address is only
present for half a clock cycle.
Figure 3–13. Isolated Read—Burst of Two (Wide Mode)
avl_clk
avl_read
avl_data_rd[19:0]
avl_wait_request_rd
avl_data_read_valid
avl_data_rd[17:0]
qdrii_k
qdrii_a[19:0]
qdrii_rpsn
qdrii_cq
qdrii_cqn
qdrii_q[17:0]
0001 0001
0102 0102
0001 0001
01 02 xx xx xx
avl_clk
avl_read
avl_data_rd[19:0]
avl_wait_request_rd
avl_data_read_valid
avl_data_rd[17:0]
qdrii_k
qdrii_a[19:0]
qdrii_rpsn
qdrii_cq
qdrii_cqn
qdrii_q[17:0]
0001 0001
0102 0102
0001 0001
01 02 02