Accelerator Functional Unit Developer Guide: Intel FPGA Programmable Acceleration Card N3000 Variants

ID 683190
Date 7/15/2022
Public
Document Table of Contents

3.2.4.5.3. QDR4 Interface

The external QDR4 SRAM is well suited for fast table look ups and external statistics counter storage due to the fast random access capabilities of QDR4 SRAM. QDR4 SRAM transfers 4 data words per clock cycle. QDR4 SRAM also has two independent bidirectional double data rate ports that support concurrent read/write transactions on both ports.

The multiple access ports of the QDR4 SRAM results in the internal interface providing 8 – Avalon® memory-mapped interface interfaces for this external memory device. The interface is shown below:

ccip_std_afu Direction Width Signal Name Description

input

 

qdr_avmm_clk

266 MHz clock sourced from EMIF

input

 

qdr_avmm_reset_n

Active low reset to user logic. Reset for the user clock domain. Asynchronous assertion and synchronous de-assertion

input

 

qdr_avmm_waitrequest [7:0]

Wait-request is asserted when controller Avalon® memory-mapped interface interface is busy

input

[35:0]

qdr_avmm_readdata [7:0]

Read data from external memory

input

 

qdr_avmm_readdatavalid [7:0]

Indicates readdata is valid when high

output

[2:0]

qdr_avmm_burstcount [7:0]

Number of transfers in each read/write burst

output

[35:0]

qdr_avmm_writedata [7:0]

AFU supplied data to written to external memory

output

[21:0]

qdr_avmm_address [7:0]

Word address for Avalon® memory-mapped interface interface of memory controller

output

 

qdr_avmm_write [7:0]

Write request from AFU

output

 

qdr_avmm_read [7:0]

Read request from AFU