Fault testing a clock distribution network

A method of fault testing a clock distribution network which fans out a clock signal to a plurality of clock signal lines, by performing the following steps on a clock signal line:

• connecting the clock signal line under test to a test latch which is set to a first logical value and has a second logic value at the input thereof;
• monitoring the output of said test latch when said clock distribution network is inhibited to ascertain whether said second logic value propagates through said test latch notwithstanding the inhibition of said clock distribution network;
• and,
• monitoring the output of said test latch when said clock distribution network is enabled, to ascertain whether said second logic value fails to propagate through said test latch, notwithstanding the enabling of said clock distribution network.

Apparatus for fault testing a clock distribution network which fans out a clock signal to a plurality of clock signal lines, comprising:

• a test latch for storing a logic value therein;
• means for storing a first logic value in said test latch and placing a second logic value at the input thereof;
• and
• means for connecting a predetermined one of said clock signal lines to said test latch;
• whereby said second logic value is stored in said test latch when said clock distribution network is enabled and said predetermined one of said clock signal lines is operating properly, and said second logic values is not stored in said test latch when said clock distribution network is inhibited and said predetermined one of said clock signal lines is operating properly.

A data processor comprising:

• at least one logic network for performing data processing operations;
• a clock distribution network for fanning out a clock signal to a plurality of clock signal lines which provide timing signals for said at least one logic network;
• and
• means for verifying the proper operation of said clock distribution network and isolating a faulty operation to a particular clock signal line.