US 2003/0227936 A1 · Data streaming for non-DMA digital computing devices

Abstract

High-speed data streams are exchanged between two digital computing devices one or both of which lacks DMA. Data transfers are performed by the devices using High-Level Datalink Control (HDLC) frames. An initiating device indicates that it wishes to exchange data with the other device by sending an HDLC frame with data stream indentification and other information. The initial HDLC frame is sufficiently short that at least an essential portion of the frame can be stored in a receive buffer of the interface circuitry. Although the receiving device may not receive the entire HDLC frame correctly because of the possibility of an overrun condition, enough information is preserved in the interface circuitry to complete the transaction. The responding device then proceeds to read or write data at high speed using a series of exchanges with the initiating device.

Claims7

Dependent claims

A method of transferring data serially between two digital computing devices without using DMA, one of the devices operating as a sender of a data block and the other device operating as a receiver of the data block, the receiver comprising interface circuitry including receive FIFO means for autonomously receiving a predetermined number of bytes of data, the method comprising the steps of:

a) sending from the sender to the receiver a poll frame an essential portion of which has a length not greater than said predetermined number of bytes;
b) interrupting the receiver, thereby causing the receiver to be completely attentive to serial communications with the sender;
c) sending from the receiver to the sender an acknowledge frame in response to said poll frame;
and
d) receiving at the receiver a data frame from the sender.

2 more elements

Dependencies are inferred from the claim text.

Data streaming for non-DMA digital computing devices

Life of this patent

Data streaming for non-DMA digital computing devices

Life of this patent

Abstract

Claims7