A built-in self test system (124) and method for two-dimensional memory
redundancy allocation. The built-in self test system is adapted to allocate two
redundant columns (116) and one redundant row (120) to an embedded
memory (104) as needed to repair single cell failures (SCFs) within the
rows (108) and columns of the memory. The self-test system includes a left-priority
encoder (136), a right-priority encoder (140), and a greater-than-two
detector (144). The left-priority encoder encodes the location of the first
SCF most proximate the most-significant bit of the corresponding word. The right-priority
encoder encodes the location of the first SCF most proximate the least-significant
bit of the corresponding word. The greater-than-two detector determines whether
a word contains more than two SCFs. If the greater-than-two detector detects that
a word contains more than two SCFs, the built-in self test system identifies the
corresponding row as being a must-fix row, since the number of SCFs exceeds the
number of redundant columns.
