Bursts with pauses, Fer to, Figure 3–15 on – Altera QDRII SRAM Controller MegaCore Function User Manual
Page 50
3–18
MegaCore Version 9.1
Altera Corporation
QDRII SRAM Controller MegaCore Function User Guide
November 2009
Interfaces & Signals
Figure 3–15. Burst—Burst of Four (Narrow Mode)
Bursts with Pauses
Bursts with pauses only applies to bursts of four, (narrow mode). When
several read requests to non-consecutive addresses occur, it takes more
time to get the data from the memory (it take two cycles per read access)
than time needed to request them.
shows a read
followed by two reads to consecutive addresses. As the first two requests
are not to consecutive addresses, the controller has to pause the read
requests to insert a clock cycle. The following two reads still get
concatenated to make a burst of four, avoiding loss of bandwidth.
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]
0002
0003
0102
0304
0304
0002
01 02 03 04
04