The present invention discloses novel methods to transfer data between a plurality of integrated circuit dice on a semiconductor wafer. Each individual die contains internal circuits to control data transfer to nearby dice. Wafer level data transfer is achieved by a series of inter-dice data transfers. It is therefore possible to use a small number of small area metal lines to support wafer level parallel processing activities. External connections are provided by a small number of bonding pads on each wafer. The load on each external bounding pad is by far lower than that of prior art wafer level connections. These inter-dice data transfer mechanism also can be programmed to avoid defective circuitry. This invention has been used to support wafer level functional tests and wafer level burn-in tests. A Testing system of the present invention can test thousands of dice in parallel using simple testing equipment. Testing costs for integrated circuits are therefore reduced dramatically. The present application also make it possible to build large area IC containing multiple dice. Extremely powerful products are realized using parallel processing capability of such multiple die integrated circuits.