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Cortex-A8 Technical Reference Manual - ARM Information Center

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11.1.4 Pattern selection<br />

CLK<br />

MBISTRESULT[1] (fail flag)<br />

MBISTDSHIFT<br />

MBISTRESULT[0] (data log shift out)<br />

Design for Test<br />

Figure 11-12 Timing of MBIST end of bitmap datalog retrieval<br />

The processor implementation includes a toolbox of patterns for testing the arrays. When<br />

creating test vectors, you can select the group of algorithms that is most effective for your<br />

fabrication process.<br />

Some of the pattern sequence descriptions use the following terms:<br />

R Read instruction data seed.<br />

W Write instruction data seed.<br />

R_ Read inverse of instruction data seed.<br />

W_ Write inverse of instruction data seed.<br />

incr Increment address starting with 0 until address = addrmax.<br />

decr Decrement address starting with addrmax until address = 0.<br />

wscan Write entire array.<br />

rscan Read entire array.<br />

N Total number of accesses per address location.<br />

Table 11-19 shows the patterns that are selected using the pttn[5:0] field of the MBIST<br />

Instruction Register.<br />

Pattern N<br />

MBISTRUN<br />

Address<br />

updating<br />

PLL glitchless switch between<br />

fast and slow clocking occurs here<br />

D[msb–1] D[msb]<br />

Description<br />

Table 11-19 Summary of MBIST patterns<br />

CAMBIST - - Tests CAM compare logic, see CAMBIST on page 11-19<br />

CKBD 4N Row-fast Checkerboard-checkerboard_bar wscan-rscan pattern, see<br />

CKBD on page 11-20<br />

COLBAR 4N Column-fast Column bar-stripe wscan-rscan pattern, see COLBAR on<br />

page 11-20<br />

ROWBAR 4N Row-fast Row bar-stripe wscan-rscan pattern, see ROWBAR on<br />

page 11-21<br />

SOLIDS 4N Row-fast Solid wscan-rscan pattern, see SOLIDS on page 11-21<br />

RWXMARCH 6N Row-fast Standard R W_ increment-decrement march, see<br />

RWXMARCH on page 11-22<br />

RWYMARCH 6N Column-fast Standard R W_ increment-decrement march, see<br />

RWYMARCH on page 11-22<br />

<strong>ARM</strong> DDI 0344K Copyright © 2006-2010 <strong>ARM</strong> Limited. All rights reserved. 11-18<br />

ID060510 Non-Confidential

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