Visible to Intel only — GUID: jmz1625848052409
Ixiasoft
Visible to Intel only — GUID: jmz1625848052409
Ixiasoft
7.3.2.1. FPGA-to-SDRAM direct (Cache Non-Allocate)
The interface from the FPGA to the SDRAM directly is AXI* 4. These transactions route directly to the EMIF circumventing the CCU and are not cached. You must manage coherency in software because the CCU is not involved with this traffic. Transactions can be privileged or non-privileged depending on Memory Allocation.
Reads
ATTRIBUTE | VALUE | NOTE |
---|---|---|
ARDOMAIN[1:0] | ‘b00 | Non-shareable. (non-coherent, non-snooping) |
ARBAR[1:0] | ‘b00 | Normal access, respecting barriers |
ARSNOOP[3:0] | ‘b0000 | ReadNoSnoop |
ARCACHE[3:0] | ‘b0010 or ‘b0011 | Normal Non-cacheable Non-bufferable (or Normal Non-cacheable Bufferable) |
ARPROT[2:0] | ‘b001 or ‘b000 | Privileged access. Secure access. Data access (could be ‘b000 for Unprivileged access) |
ARLEN[7:0] | The burst length for: WRAP burst type must be 1, 2, 4, 8 or 16 transfers. INCR burst type is 1 to 256 transfers. |
|
ARSIZE[2:0] | The number of bytes in a transfer must be equal to the data bus width (32, 64, or 128 bits) | |
ARBURST[1:0] | ‘b01 or ‘b10 | Must be INCR(‘b01) or WRAP(‘b10) |
ARLOCK[1:0] | ‘b00 | Must be normal access |
ARQOS | Quality of Service. QoS identifier sent for each transaction. Implemented only in AXI4. |
Writes
ATTRIBUTE | VALUE | NOTE |
---|---|---|
AWDOMAIN[1:0] | ‘b00 | Non-shareable. (non-coherent, non-snooping) |
AWBAR[1:0] | ‘b00 | Normal access, respecting barriers |
AWSNOOP[2:0] | ‘b000 | WriteNoSnoop |
AWCACHE[3:0] | ‘b0010 or ‘b0011 | Normal Non-cacheable Non-bufferable (or Normal Non-cacheable Bufferable) |
AWPROT[2:0] | ‘b001 or ‘b000 | Privileged access. Secure access. Data access (could be ‘b000 for Unprivileged access) |
AWLEN[7:0] | The burst length for: WRAP burst type must be 1, 2, 4, 8 or 16 transfers. INCR burst type is 1 to 256 transfers. |
|
AWSIZE[2:0] | The number of bytes in a transfer must be equal to the data bus width (32, 64, or 128 bits) | |
AWBURST[1:0] | ‘b01 or ‘b10 | Must be INCR(‘b01) or WRAP(‘b10) |
AWLOCK[1:0] | ‘b00 | Must be normal access |
AWQOS | Quality of Service. QoS identifier sent for each transaction. Implemented only in AXI4. |