Memory interface circuit and semiconductor device

Abstract

There is a need to provide a small-sized memory interface circuit capable of adjusting timing between a strobe signal and a data signal without interrupting a normal memory access. An expected value acquisition latch latches write data in synchronization with a clock signal. A WDLL outputs a write strobe signal WDQS. An RDLL outputs a delayed write strobe signal WDQS_d. A read data latch latches looped-back write data in synchronization with the delayed write strobe signal WDQS_d. A comparator compares the read data latch with an output from the expected value acquisition latch. A register portion stores a delay value to be placed in the RDLL. A register control portion updates a delay value in the register portion in accordance with a comparison result. A delay selection portion places a delay value read from the register portion in the RDLL.

Dependencies are inferred from the claim text.