A controller includes a link interface that is to couple to a first link to communicate bi-directional data and a second link to transmit unidirectional error-detection information. An encoder is to dynamically add first error-detection information to at least a portion of write data. A transmitter, coupled to the link interface, is to transmit the write data. A delay element is coupled to an output from the encoder. A receiver, coupled to the link interface, is to receive second error-detection information corresponding to at least the portion of the write data. Error-detection logic is coupled to an output from the delay element and an output from the receiver. The error-detection logic is to determine errors in at least the portion of the write data by comparing the first error-detection information and the second error-detection information, and, if an error is detected, is to assert an error condition.