3.3.2. Maximum Number of Outstanding Transactions Register

The max_ot Register characteristics are:

Purpose

This register enables you to program the maximum number of address requests for the AR and AW channels. See Outstanding transaction regulation for more information.

The outstanding transaction limits have an integer part and a fractional part as follows:

ar_max_oti

Corresponds to the integer part of the maximum outstanding AR addresses.

aw_max_oti

Corresponds to the integer part of the maximum outstanding AW addresses.

ar_max_otf

Corresponds to the fractional part of the maximum outstanding AR addresses.

aw_max_otf

Corresponds to the fractional part of the maximum outstanding AW addresses.

A value of 0 for both the integer and fractional parts disables the programmable regulation so that the NIC-400 base product configuration limits apply.

The AW and AR outstanding transaction limits are enabled when you set the corresponding en_aw_ot or en_ar_ot control bits of the QoS control register. See QoS Control Register and Table 3.2.

Usage constraints

You cannot increase the limits above either:

  • the configuration limits you set at design time

  • the CoreLink NIC-400 Network Interconnect limit of 32.

Configurations

Only available when you select outstanding transaction regulation in AMBA Designer.

Attributes

Figure 3.2 shows the bit assignments.

Figure 3.2. max_ot Register bit assignments

To view this graphic, your browser must support the SVG format. Either install a browser with native support, or install an appropriate plugin such as Adobe SVG Viewer.


Table 3.3 shows the bit assignments.

Table 3.3. max_ot Register bit assignments

BitsNameFunction
[31:30]-Reserved. Do not modify. Read as zero.
[29:24]ar_max_otiInteger part of the maximum outstanding AR addresses.
[23:16]ar_max_otfFractional part of the maximum outstanding AR addresses.
[15:14]-Reserved. Do not modify. Read as zero.
[13:8]aw_max_otiInteger part of the maximum outstanding AW addresses.
[7:0]aw_max_otfFractional part of the maximum outstanding AW addresses.

Copyright © 2012, 2013 ARM. All rights reserved.ARM DSU 0026B
Non-ConfidentialID051113