Micron Technology, Inc.
Combined write enable mask and credit return field

Abstract:

A credit return field is used in a credit-based flow control system to indicate that one or more credits are being returned to a sending device from a receiving device. Based on the number of credits available, the sending device determines whether to send device or wait until more credits are returned. A write enable mask allows a wide data field to be used even when a smaller amount of data is to be written. A novel data packet uses a combined write enable mask and credit return field. In one mode, the field contains a write enable mask. In another mode, the field contains credit return data. If the field contains credit return data, a default value (e.g., all ones) is used for the write enable mask. The mode may be selected based on another value in the data packet.