In order to execute the electronic circuit design which includes the access impossible node which is not jointed to

摘要

PROBLEM TO BE SOLVED: To improve facility in access to an internal cell in a prototype or final circuit environment by including a means, etc., for emulating a test object PLD(programmable logical device). ;SOLUTION: A shadow PLD 304 is programmed so as to emulate one of or both of function property and a timing in PLD 1011. PLD 304 is provided with a circuit block 309 which is functioned in the same way as the circuit block 109. Since PLD 304 is programmed so as to emulate PLD 104 being the test object, most of the I/O terminals of PLD 104 such as terminals 101a-101d are connected to the similar I/O terminals such as 301a-301d of PLD 304. Moreover, switches 322a-322d are closed so that the terminals 301a-301d are connected to the input terminals 101a-101d. Thus, access is made to be possible to a node inside PLD, analysis is simplified and multiple pieces of information of an analyzed object are obtained.;COPYRIGHT: (C)1998,JPO