The actual test program, this is created individually for each assembly.
Special technologies (guarding) allow the influence of surrounding components to be eliminated. In this way, test coverage of >90% can be achieved in many cases.
The test spectrum of the ICT includes:
Depending on the devices to be programmed, up to 128 identical devices can be programmed simultaneously using the first two methods mentioned (utility programming). It is also possible to write variable data such as individual serial numbers.
In addition, necessary test points are often omitted for space or EMC reasons.
The Boundary Scan Test (BST) was standardized in 1990 under IEEE 1149.1. Boundary scan can be used to perform electrical tests on assembled printed circuit boards. In addition to the core logic, boundary-scan-capable chips have an additional logic, the boundary-scan cell, with a test access port (TAP). Physical access in boundary-scan is via four interconnect lines.
The test spectrum of the BST includes:
Depending on the devivce, different technologies are used for the AST:
In addition to pure testing for function, other functions can also be realized:
The force required for this is generated mechanically on individual test stations by vacuum and when integrated into production lines. Contact can be made on one or both sides.