| 摘要 |
An electronic circuit contains groups of flip-flops ( 12 a-c), coupled to data terminals ( 11 a-c) of the circuit and to a functional circuit ( 10 ). Each group ( 12 a-c) has a clock input for clocking the flip-flops of the group. Each group ( 12 a-c) can be switched between a shift configuration and a functional configuration, for serially shifting in test data from the data terminals and to function in parallel to supply signals to the functional circuit ( 10 ) and/or receive signals from the functional circuit ( 10 ) respectively. A test control circuit ( 16 ) can be switched between a functional mode, a test shift mode and a test normal mode. The test control circuit ( 16 ) is coupled to the groups of flip-flops ( 12 a-c) to switch the groups to the functional configuration in the functional mode and to the shift configuration in the test shift mode. A clock multiplexing circuit ( 15 a-c, 18 ) has inputs coupled to the data terminals ( 11 a-c) and outputs coupled to clock inputs of the groups ( 12 a-c). The test control circuit ( 16 ) is coupled to control the clock multiplexing circuit ( 15 a-c, 18 ) dependent on the mode assumed by the test control circuit ( 16 ). The clock multiplexing circuit ( 15 a-c, 18 ) is arranged to substitute clock signals from respective ones of the data terminals ( 11 a-c) temporarily at the clock inputs of respective ones of the groups ( 12 a-c) in the test normal mode.
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