ARM NIC-301 User Manual

ARM DDI 0397G

2-10

ID031010

You can configure the following options for the AHB interface:

•

Address width of 32-64 bits.

•

Data width of 32, 64, 128, or 256 bits.

•

Data width upsize function that Upsizing data width function on page 2-12 describes.

•

Data width downsize function that Downsizing data width function on page 2-14 
describes.

•

Frequency domain crossing of the following types:
—

ASYNC

—

SYNC  1:1

—

SYNC  1:n

—

SYNC  n:1

—

SYNC  n:m.

•

Security of the following types:
Secure 

Only secure transactions can access components attached to this master 
interface.

Both secure and non-secure transactions can access components attached to 
this master interface.

You can use software to configure whether it permits secure and non-secure 
transactions to access components attached to this master using the Secure and 
Non-secure options above.

•

Support for the full AHB-Lite master protocol.

•

Timing isolation:
—

from the external slave

—

from the network.

You can configure the APB interface to support a mixture of APB2 or APB3. The APB data 
width is always 32-bit, and it is therefore never necessary for the APB interface to require the 
upsize function. The APB interface can ignore AXI writes strobes. If the network receives a 
write transaction with all of the write strobes negated, then it does not perform the write.

 APB SLVERR responses are converted to AXI SLVERR responses.

Any transaction that the network receives without all four WSTRBs asserted or negated still 
goes ahead. This means that erroneous data bytes might be written to the slave. The masters 
accessing the APB interface ensure that only WORD writes access the APB sub-system. The 
address and data widths are fixed as follows:
•

address width of 32-bit

•

data width of 32-bit.