Re: AHB protocol document - clarification


Charles, NG wrote:

I seem to remember this being explained elsewhere in the spec as well,
but basically it has to do with how a slave recognises whether it is the
target of a request or not. A slave recognises selection when HTRANS =
NSEQ and its HSEL is active. For the rest of a burst transfer (HTRANS =
SEQ), a slave can continue to consider itself selected until it sees
either a new address cycle with HTRANS = NSEQ or HTRANS = IDLE. If a
master bursted across a 1K boundary (i.e. into the next page) the first
slave might or might not remain selected and the second slave might or
might-not pick up selection (it really shouldn't though even if it's
HSEL = 1 when HTRANS != NSEQ)

So really the two statements are the two different views to the AMBA AHB
rules for memory-space granularity. The first statement is from the
slave point of view and the second statement is from the master point of
view.


hi,
A new page doesn't mean a new slave .Because the first statement says
that the minimum address space of a slave should be 1k and so no limit
on maximum space.
So if the 1k boundary is crossed ,it shouldn't matter as there is HSEL
signal to select a slave which is a combinatorial decode of higher
order address bus.
Could n't get what you were trying to explain....

regards,
Anupam Jain

.

Relevant Pages

  • Re: AHB protocol document - clarification
    ... The minimum address space that can be allocated to a single slave is 1kB. ... This refers to the memory granularity when designing your memory map. ... A slave recognises selection when HTRANS = ... might-not pick up selection (it really shouldn't though even if it's ...
    (comp.lang.vhdl)
  • Re: 5.2-RELEASE: unable to mount cd-roms
    ... It seems Jon Noack wrote: ... That was in a very different context where one master device responded to ... both master and slave selection... ...
    (freebsd-current)