• State Suggested Answer
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 350 subscribers
  • Views 1268 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

About PSTRB...

jh_s

PSTRB signal of APB indicates the valid write byte lanes.

If the width of PSTRB is 4,

Must I use only 4'b1111 or 4'b0000 of PSTRB before APB4?

Can I use 4'b0110 of PSTRB after APB3?

Parents
  • 0

    If you are trying to connect an APB4 target with a PSTRB input to an APB3 (or earlier) source which doesn't have a PSTRB output, you would have to drive PSTRB=4'b1111 for writes and 4'b0000 for reads (spec says PSTRB must not be active for reads).... so basically use PWRITE to drive the target's PSTRB input bits.

    For an APB4 source it can drive PSTRB to any value, including 4'b0110.

Reply
  • 0

    If you are trying to connect an APB4 target with a PSTRB input to an APB3 (or earlier) source which doesn't have a PSTRB output, you would have to drive PSTRB=4'b1111 for writes and 4'b0000 for reads (spec says PSTRB must not be active for reads).... so basically use PWRITE to drive the target's PSTRB input bits.

    For an APB4 source it can drive PSTRB to any value, including 4'b0110.

Children
No data