6402 datasheet(120/250 Pages) INTEL

120 / 250 page

DDR MemBIST

120

Intel® 6400/6402 Advanced Memory Buffer Datasheet

11.3.2.4.3

Fast XY

In Fast XY execution, both the X and Y address counters are changed by one count at

the same time. Each of these counters begins at its starting address and increments to

its ending address (or decrements from ending to starting address if so programmed)

and then reloads on the next count to its initial value. As a result, test execution

accesses the RAM locations in diagonal rows across the RAM. Execution stops when

both the X and Y address counters reach their end values simultaneously.

In the special case when there are the same number of rows and columns in the

address space, only the locations on the diagonal (whose relative row and column

positions are equal) will be tested. In the general case in which the specified address

range results in different numbers of rows and columns, not all locations may be

accessed. Which locations are accessed in this case depends upon the X to Y ratio of

the address space specified for the test. See Figure 11-4 below for several examples.

Because the starting and ending addresses are always located at opposite corners of

the address space, the end address is always eventually reached, and the MemBIST

operation always completes.

Figure 11-3. Fast X Address Sequencing

One Bank

0 Increasing Y

Increasing X

Address space as set by values in MTR register

Address space as set by start and end values in

MB_START_ADDR and MB_END_ADDR registers

0001

Fast X address sequencing, decreasing

address, specified address range

6402 Datasheet(PDF) 120 Page - Intel Corporation