Memory controller useable for a dynamic random access memory (dram) health monitor

Abstract

A memory controller includes a first storage circuit which stores trained center eyes for a dual data rate (DDR) interface, each trained center eye including a corresponding trained delay value, and a second storage circuit which stores boundary points for the DDR interface. The memory controller includes test circuitry which halts normal operation and uses a corresponding trained delay value of a trained center eye for a first bit lane of the DDR interface as a starting delay value in performing a search for a first boundary point of a data eye margin by repeatedly adjusting a delay between a data signal (DQS) of the first bit lane and a corresponding data strobe signal (DQS) and performing a test with each adjusted delay. The test circuitry stores the first boundary point in the second storage circuit, restores the delay back to the corresponding trained delay value, and resumes normal operation.