A structure, and corresponding operating techniques, are presented for the internal controller to memory circuit interface for memory systems such a flash memory card or other similarly structured devices. The interface between the controller circuit and memory circuit (or circuits) includes a feedback process where the amount of error that arises due to controller-memory transfers is monitored and the transfer characteristics (such as clock rate, drive strength, etc.) can be modified accordingly. For example, in addition to transferring a set of data, the transmitting side also generates and transmits a corresponding hash value for the set of data. When the set of data is received on the other side, a hash value is also generated there and compared to the received hash value to determine if these was transmission error. If there is no error, the transfer rate could, for example, be increased, while if there were error, it could be decreased.