| 摘要 |
A system for the debugging of integrated circuit designs containing a plurality of macrocells A, B and C utilises multiplexers 68, 70 and 72 associated with external output connections 62, 64 and 66 to select either a normal external output signal 42, 48 and 52 diagnostic internal signal. In operation, a primary integrated circuit and a tracking integrated circuit (see fig.6) may be supplied with identical input signals and so adopt identical states. The primary integrated circuit selects the normal external output signals whilst the tracking integrated circuit selects for diagnostic purposes predetermined internal signals. A further tracking integrated circuit 74 may be provided that corresponds to one of the macrocells A within the primary integrated circuit and the tracking integrated circuit to provide further details of the operation of this macrocell. |
