Unidirectional error code transfer for a bidirectional data link

A computer readable medium containing data representing a circuit that includes:

• a link interface, wherein the link interface is to couple to a first link to communicate bi-directional data and a second link to transmit unidirectional error-detection information;
• a first encoder to dynamically generate first error-detection information for at least a portion of write data;
• a first transmitter coupled to the link interface, wherein the first transmitter is to transmit the write data;
• a first delay element coupled to an output from the first encoder;
• a first receiver coupled to the link interface, wherein the first receiver is to receive second error-detection information corresponding to at least the portion of the write data;
• and
• error-detection logic coupled to an output from the first delay element and an output from the first receiver,
• wherein the error-detection logic is to detect errors in at least the portion of the write data based on the first error-detection information and the second error-detection information, and, if an error is detected, is to assert an error condition.

A memory system, comprising:

• a memory device having device-side logic to generate device error detection codes for incoming write data and outgoing read data;
• a controller having:
• controller-side logic to generate controller error detection codes for outgoing write data and incoming read data,
• a data transmitter that transmits write data to the memory device,
• a data receiver that receives read data from the memory device, and
• an error detection mechanism to detect errors for the write data and the read data based on the device error detection codes and the controller error detection codes;
• and
• a bus interface coupling the controller and the memory device, including bi-directional data communication routing for carrying read data and write data, and a uni-directional error detection code link for transmitting the device error detection codes to the controller.

A method of operating a controller, comprising:

• dynamically generating first error-detection information for at least a portion of data, wherein the data is one of:
• outgoing write data and incoming read data;
• when the data is write data,
• receiving from a remote device, second error-detection information corresponding to at least the portion of the write data as received by the remote device, and
• detecting errors in at least the portion of the write data based on the second error-detection information and a delayed version of the first error-detection information, and, if an error is detected, to assert a first error condition;
• and
• when the data is read data,
• receiving from the remote device, third error-detection information corresponding to at least the portion of the read data as transmitted by the remote device, and
• detecting errors in at least the portion of the read data based on the third error-detection information and the first error-detection information, and, if an error is detected, to assert a second error condition.