Patent ID: 7652503

Claim:
A semiconductor device comprising: an external pin; a control parameter decision circuit including: a register that is initialized in accordance with resetting of the semiconductor device; an output selector that selects, according to a level value of an external input signal supplied via said external pin, one of a signal whose level value is set equal to a register value of said register and a signal whose level value is set opposite to the register value of said register, and outputs the selected signal as a control parameter signal; and a register update circuit that updates the register value of said register when a level value of said control parameter signal need be changed, wherein the register value of said register is set to a level value of a write data signal in response to activation of a write request signal, and when the level value of said control parameter signal need be changed, the register update circuit activates the write request signal and sets the level value of the write data signal according to the level value of the control parameter signal and the level value of the external input signal.