Arria V Hard Processor System Technical Reference Manual

ID 683011
Date 12/02/2022
Public
Document Table of Contents

14.4.4. Local Memory Buffer

The NAND flash controller has three local SRAM memory buffers. Of the three, only the read and write clocks are asynchronous.
  • ECC buffer—Operates at the core clock, it enables the simultaneous process between sending out the data to the host and receiving data from the device to achieve a line rate operation.
  • Write FIFO—The write port operates at aclk and the read port operates at clk. The buffer must be large enough to pre-allocate all the read data associated with the number of the outstanding read requests that it could issue to the hosts. Up to 8 outstanding read requests are supported, with a maximum burst size of 64 bytes. Therefore, the write FIFO buffer is a 128 × 32-bit memory (512 total bytes).
  • Read FIFO—The read port operates at aclk and the write port operates at clk. Regardless of the number of outstanding read requests that it could receive from the host, it only requires a buffer size that is just enough to sustain the streaming from the device memory to the system bus. Therefore, the read FIFO buffer is a 32 × 32-bit memory (128 total bytes). Since the size of the read FIFO is relatively small for SRAM implementation, it can be implemented using flops.