I'm trying to understand the write strobe functionality for a 128bit bus width, burst type FIXED.
Case scenario:
AXI bus width 128bit.
awlen = 3 (4 write transfers)
awsize = 2 (32bit per each transfer)
awburst = 0 (FIXED)
awaddr = 0x6116_0304;
How will the write strobe look like throughout the burst?.
1. 0x00f0, 0x0f00, 0xf000, 0x000f
or
2. 0x00f0, 0x00f0, 0x00f0, 0x00f0
Please explain why.
Many thanks.
Tsach
Hello Tsach,
For a FIXED burst, the byte lanes for each beat is fixed, determined by the address and size of the burst.
Since this is a FIXED-4 x 32-bit transaction to address 0x04, so the only valid byte lanes would be [63:32]. Therefore, "2. 0x00f0, 0x00f0, 0x00f0, 0x00f0" is correct.
Regards,
Xingguang