Transparent data bus sizing
US5388227A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 7, 1992 |
| Grant date | Feb 7, 1995 |
| Priority date | — |
| Expiry date | Oct 7, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F13/4018
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A bus system wherein N-bit devices (12b,12c) attached to the lower half (30L) of a 2N-bit bus (30) communciate with 2N-bit (12a, 12d) devices attached to the full bus. Bi-directional registered transceivers (60,62,65,67) are coupled between the upper and lower halves of the bus. The N-bit devices are capable of asserting a pair of signals called HOLDN and LATCHN. For a 2 N-bit source device transmitting data to an N-bit sink device, the 2 N-bit source puts 2 N bits of data on the upper and lower halves of the bus during a given cycle, during which the N-bit sink device samples the N bits on the lower half of the bus. The assertion of HOLDN causes the N bits on the upper half of the bus to be latched and subsequently driven onto the lower half of the bus. Where an N-bit source device is communicating to a 2 N-bit sink device, the N-bit device puts the high order N bits and low order N bits of data on the lower half of the bus on successive cycles. During the cycle that the high order bits are on the bus, the N bit source device asserts LATCHN which causes the data to be latched and then driven onto the upper half of the bus during the subsequent cycle,
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.