An input/output pin for test corresponding to a test circuit of the digital section
is used in common as the input/output pin for normal operation of the analog section.
The selection switches are respectively provided between the relevant analog pin
and analog circuit and on a signal line up to the test circuit of the digital section
from the relevant analog pin and the switches are provided at both end portions
of the signal line between the test circuit of digital section and the input/output
pin for common use in order to fix the voltage of the signal line to the predetermined
voltage such as the ground voltage during the normal operation. Thereby, it is
possible in a semiconductor integrated circuit having the analog and digital sections
to eliminate adverse effect, even if the input/output pin for testing corresponding
to the test circuit of the digital section is used in common as the input/output
pin for normal operation of the analog section, from the analog circuit due to
the noise which is generated in the digital section and is then transferred to
the analog circuit through the signal path up to the analog input/output pin connected
to the test circuit from this test circuit of the digital section.
