A semiconductor integrated circuit device comprises a control unit for
switching a mode about the trimming or estimation in an internal circuit,
the control unit including a controller capable of realizing the mode
switching control about the trimming or estimation by the JTAG method. The
controller includes an instruction decoder for decoding an input
instruction, a shift scan register circuit for enabling a boundary scan
based on the decoded result of the instruction decoder, and an operation
controller for controlling the operations of the instruction decoder and
the shift scan register circuit. Therefore, the trimming becomes possible
after sealing a semiconductor chip into a package.
