Serial communication method and apparatus
US5701330A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 16, 1994 |
| Grant date | Dec 23, 1997 |
| Priority date | — |
| Expiry date | Dec 16, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2007/047
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Two or more communication modules are coupled by a one wire transmission line. A feed module impresses dc power and a sine wave carrier signal on the line. Each module generates a square wave signal synchronous with the carrier, each period of the signal representing one data bit. Data is written onto the line by a module by attenuating the carrier wave for selected bits and read by another module by sampling the bits and detecting those which are attenuated. Address and message data is transmitted in packets of n bits, the first bit always being an attenuated bit. Addressing is accomplished by generating a sequence of n unattenuated bits and then writing packets of address data. An address is valid when it matches a stored address in a module and that module is then activated to read or write. Multiple addressing modules can be used with a priority technique which reserves a priority code location at the beginning of an address string and compares code bits of a sending module with carrier bits, and aborts the address write when the carrier has an attenuated priority bit and the sending module is attempting to send an unattenuated bit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.