Data communication method and apparatus utilizing credit-based data transfer protocol and credit loss detection mechanism
US7136954B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 31, 2005 |
| Grant date | Nov 14, 2006 |
| Priority date | — |
| Expiry date | Jun 6, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F13/36
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A communications bus for a digital device includes a credit-based flow control mechanism, in which a sending component maintains a local record of its credits. Credits are returned to the sender by pulsing a single-bit credit return line. A separate mechanism provides a count of available credits from the receiver, the separate mechanism not necessarily being current. The local record is compared to the count of credits from the separate mechanism over a pre-determined time interval, failure of the two values to agree at any time during the interval indicating a probable credit discrepancy. A credit discrepancy is confirmed, preferably by suspending certain bus activity for a sufficiently long period to account for any delay in propagating credit value changes, and re-comparing the values. Preferably, the bus communicates between internal components of an integrated circuit chip.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.