ARM AMBA NIC-301 User Manual

Functional Description

ARM DDI 0397G

2-13

ID031010

Non-Confidential

INCR bursts

The network converts all input INCR bursts that complete within a single output data width into
an INCR1 of the minimum SIZE possible, and it packs all INCR bursts into INCR bursts of the
optimum size possible. Table 2-3 shows how the network converts INCR bursts when it upsizes
them.

WRAP bursts

All WRAP bursts are either passed through unconverted as WRAP bursts, or converted to one
or two INCR bursts of the output bus. Table 2-4 shows how the network converts WRAP bursts
when it upsizes them from 64-bit to 128-bit, that is, a ratio of 1:2.

Note

The network converts input WRAP bursts with a total payload that is less than the output data
width to a single INCR.

Fixed bursts

All FIXED bursts pass through unconverted.

Bypass merge

You can configure the upsizer function to have a programmable bit named

bypass_merge

. If

bypass_merge

is asserted, the network does not alter any transactions that could pass through

legally without alteration.

Table 2-3 Conversion of INCR bursts by the upsize function

INCR burst type

Converted to

64-bit INCR1

Passes through unconverted

64-bit aligned INCR2

INCR1

8-bit aligned INCR8

INCR1, 128-bit

8-bit unaligned, byte address 1, 2, or 3, INCR5

INCR1, 128-bit

8-bit unaligned, byte address 4, 5, 6, or 7, INCR5

INCR2, 64-bit

64-bit unaligned INCR2

Passes through unconverted

64-bit aligned INCR4

INCR2

64-bit unaligned INCR4

Sparse INCR3

Table 2-4 Conversion of WRAP bursts by the upsize function

WRAP burst type

Converted to

64-bit aligned WRAP2

INCR1

64-bit aligned WRAP4

WRAP2

64-bit unaligned WRAP4

Depending on the address:
•

INCR2 + INCR1

•

INCR1 + INCR2