Altera QDRII SRAM Controller MegaCore Function Bedienungsanleitung PDF herunterladen (Seite 45)

Altera Corporation MegaCore Version 9.1 3–13

November 2009 QDRII SRAM Controller MegaCore Function User Guide

Functional Description

Figure 3–9. Write—Burst of Four (Wide Mode)

Bursts

Bursts are only possible on the Avalon side in the burst of two mode,

where you can transfer data every clock cycle and in bursts of four

(narrow mode). It is not possible in the burst of four (wide mode), because

it takes two QDRII SRAM clock cycles to transfer one Avalon clock cycle

of data.

Figure 3–10 on page 3–14 shows the burst of four (narrow mode). When

two write requests are sent on the Avalon interface at consecutive

addresses, the controller automatically concatenates them and transfers

them to the QDRII SRAM, if the first one is an even address. If more data

is coming in the following cycle, it is also sent straight away, without any

pause.

avl_write

avl_data_wr[35:0]

avl_adr_wr[19:0]

avl_wait_request_wr

system_clk

qdrii_d[17:0]

qdrii_a[19:0]

qdrii_bwsn[1:0]

qdrii_wpsn

0102030401020304

00010001

01 02 03 0404

00010001

0000

avl_clk

avl_clock_wr

1 2 ... 40 41 42 43 44 45 46 47 48 49 50 ... 67 68

Keine Kommentare

Altera QDRII SRAM Controller MegaCore Function Bedienungsanleitung Seite 45