• State Not Answered
  • Locked Locked
  • Replies 4 replies
  • Subscribers 92 subscribers
  • Views 12675 views
  • Users 0 members are here
Options
Related
How was your experience today?
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

the usage of WSTRB signal

Dong Luo
Note: This was originally posted on 26th February 2009 at http://forums.arm.com

Hi All,
I was going through the AMBA AXI specs, but I have some questions about the usage of the WSTRB signal. In the middle of a burst, can some bits of WSTRB be low? Again, in the last transfer of a burst, can some bits of WSTRB be low? For example, assuming the data bus is 32-bit wide and in the middle of a burst, can I transfer data 0x11xx22xx(x means don't care) and set  WSTRB to be 0b1010 ? Thanks in advance.
Parents
  • 0
    Note: This was originally posted on 2nd March 2009 at http://forums.arm.com

    Hi JD,
    Sorry. I think I didn't describe my questions clearly. So I will describe my questions in more detail this time.
    Question 1:
    assuming the address bus and data bus are 32-bit wide. In the first transfer of a burst, I want to write 4 byte data to the address of 0x00000000 and of course, AWSIZE is 3'b010 and WSTRB is 4'b1111. In the second transfer, I want to write 1 byte data to the address of 0x00000005 and 1 byte data to the address of 0x00000007. Can I set AWSIZE to be 3'b010 and set WSTRB to be 4'b1010? In the third transfer, I want to write 4 byte data to the address of 0x00000008 and of course, AWSIZE is 3'b010 and WSTRB is 4'b1111. If I can do the second transfer in my way, will the slave's address register be added by 4 to prepare for receiving the next transfer's data?


    Question 2:
    assuming the address bus and data bus are 32-bit wide. In the first transfer of a burst, I want to write 2 byte data to the address of 0x00000000 and of course, AWSIZE is 3'b001 and WSTRB is 4'b0011. Will the slave's address register be added by 2 to prepare for receiving the next transfer's data?


    Question 3:
    assuming the address bus and data bus are 32-bit wide. In the first transfer of a burst, I want to write 1 byte data to the address of 0x00000001 and 1 byte data to the address of 0x00000003. Can I set AWSIZE to be 3'b001 and WSTRB to be 4'b1010? Will the slave's address register be added by 4 to prepare for receiving the next transfer's data?


    Would you please take some time to explain the three questions for me? Thanks in advance.
Reply
  • 0
    Note: This was originally posted on 2nd March 2009 at http://forums.arm.com

    Hi JD,
    Sorry. I think I didn't describe my questions clearly. So I will describe my questions in more detail this time.
    Question 1:
    assuming the address bus and data bus are 32-bit wide. In the first transfer of a burst, I want to write 4 byte data to the address of 0x00000000 and of course, AWSIZE is 3'b010 and WSTRB is 4'b1111. In the second transfer, I want to write 1 byte data to the address of 0x00000005 and 1 byte data to the address of 0x00000007. Can I set AWSIZE to be 3'b010 and set WSTRB to be 4'b1010? In the third transfer, I want to write 4 byte data to the address of 0x00000008 and of course, AWSIZE is 3'b010 and WSTRB is 4'b1111. If I can do the second transfer in my way, will the slave's address register be added by 4 to prepare for receiving the next transfer's data?


    Question 2:
    assuming the address bus and data bus are 32-bit wide. In the first transfer of a burst, I want to write 2 byte data to the address of 0x00000000 and of course, AWSIZE is 3'b001 and WSTRB is 4'b0011. Will the slave's address register be added by 2 to prepare for receiving the next transfer's data?


    Question 3:
    assuming the address bus and data bus are 32-bit wide. In the first transfer of a burst, I want to write 1 byte data to the address of 0x00000001 and 1 byte data to the address of 0x00000003. Can I set AWSIZE to be 3'b001 and WSTRB to be 4'b1010? Will the slave's address register be added by 4 to prepare for receiving the next transfer's data?


    Would you please take some time to explain the three questions for me? Thanks in advance.
Children
No data