09.12.2012 Views

Cortex-A8 Technical Reference Manual - ARM Information Center

Cortex-A8 Technical Reference Manual - ARM Information Center

Cortex-A8 Technical Reference Manual - ARM Information Center

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

Integer data and CP14 writes Noncacheable/cacheable<br />

Write-through/strongly ordered<br />

External Memory Interface<br />

The processor supports multiple read and write channel transactions as Table 9-3 shows.<br />

9.2.2 Read/write data bus width configuration pin<br />

The primary input pin A64n128 of the processor determines the width of the AXI interface<br />

read/write data buses. You must ensure that this pin is driven appropriately for your system<br />

configuration.<br />

Table 9-4 shows the supported values for A64n128.<br />

<strong>ARM</strong> DDI 0344K Copyright © 2006-2010 <strong>ARM</strong> Limited. All rights reserved. 9-4<br />

ID060510 Non-Confidential<br />

b0000<br />

Cacheable non-burst writes b0010<br />

Shared device b0001<br />

Nonshared device b0011<br />

NEON and VFP writes Noncacheable/cacheable<br />

Write-through/strongly ordered<br />

Table 9-2 Write address channel AXI ID (continued)<br />

Write address channel request type ID tag value<br />

b0000<br />

Cacheable non-burst writes b0010<br />

Shared device b0001<br />

Nonshared device b0011<br />

PLE L2 cacheable b1000-b1011<br />

CP15 (cache maintenance) L2 cacheable b1000-b1011<br />

Table 9-3 AXI master interface attributes<br />

Attribute Outstanding transactions<br />

Write Issuing Capability 12<br />

Read Issuing Capability 18<br />

Combined Issuing Capability 26 a<br />

a. The combined issuing capability is limited to a total of four<br />

outstanding linefills or evictions. Therefore the sum of the<br />

read and write issuing capability does not equal the<br />

combined issuing capability.<br />

Table 9-4 A64n128 encoding<br />

Value Description<br />

0 128-bit interface<br />

1 64-bit interface

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!