IEEE Standard 1149.1 (JTAG) in the 3200DX Family

Due to the increasing complexity of circuit boards, testing loaded boards is becoming prohibitively expensive and more difficult to perform. Board complexity has resulted from the rapid development of surface-mount technology and from the use of multilayered boards. Finer pin spacing and the use of double-sided boards also have contributed to the increased cost and difficulty of traditional testing, which makes use of methods such as in-circuit testing by bed-of-nails and functional testing. Although functional testing can cope with complex and dense boards, it is costly because different designs require different sets of test programs.