A structure comprising a memory chip and a tester for testing the memory
chip, and a method for operating the structure. The memory chip comprises
a BIST (Built-in Self Test) circuit, a plurality of RAMs (Random Access
Memories). A first RAM is selected for testing by scanning in a select
value into a RAM select register in the BIST. While the BIST performs a
first testing pass for the first RAM, the tester collects cycle numbers
of the failing cycles. Then, the BIST performs a second testing pass for
the first RAM. At each failing cycle identified during the first testing
pass, the BIST pauses so that the content of the location of the first
RAM associated with the failing cycle and the state of the BIST can be
extracted out of the memory chip. The testing procedures for the other
RAMs are similar to that of the first RAM.