A useful semiconductor processing device (LSI) is capable of implementing the precise setting of signals at the final stage of user system development and enabling the user to build a logic circuit in the device in a very short time. The LSI includes a CPU, a flash memory which is a nonvolatile memory, a programmable logic which is a SRAM-type field programmable gate array, and a configuration circuit which implements the logic circuit configuration operation. At the event of power-on reset, logic building data stored in the flash memory is transferred to the programmable logic to establish a logic circuit in it under control of the configuration circuit, so that the logic circuit built in the programmable logic can be used immediately after the power-on reset of the device.