The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 14, 1992
Filed:
Oct. 11, 1989
Jordan R Silver, San Jose, CA (US);
Tandem Computers Incorporated, Cupertino, CA (US);
Abstract
A circuit for controlling data transfer handshake protocol so that certain protocol events may occur prior to or simultaneously with the completion of a proceeding protocol event, and the ultimate results of the pending protocol event may be determined at a later time. In one embodiment of the invention a CPU operates to transfer data (either receive or send) between itself and an I/O channel every five processor clock cycles. At the beginning of each set of five clock cycles the CPU places data on the data bus and generates a transfer request (CPU-XFR) signal whenever it receives a data accepted (DATA-ACC) signal indicating that a previous data transfer has occurred. The CPU-XFR signal is generated regardless of whether or not the previous data transfer is complete at the time. The data transfer normally is completed one clock cycle after the CPU-XFR signal is generated, and at that time a transfer complete signal is generated. If the transfer complete signal is not generated, a transfer inhibits signal is generated for inhibiting the generation of the succeeding DATA-ACC signal and hence the next CPU-XFR signal.