Process for information transmission in a bus system having several participants
First Claim
1. Process for serially transmitting information entities over a serial bus between a plurality of subscribers (ECU1 to ECU4) connected to said serial bus at a common transmission rate for all of said subscribers, each of said subscribers transmitting said information entities at said common transmission rate, said process comprising the steps of:
- a) providing each of said information entities with a start bit (Sta), said start bit (Sta) being transmitted on said serial bus at a beginning of transmission of each of said information entities;
b) prior to transmitting said information entities on said serial bus each of said subscribers transmitting said information entities waits a predetermined bus monitoring time period prior to said transmitting;
c) setting a flag after one of said subscribers (ECU1 to ECU4) receives one of said information entities, said flag being set indicating receipt of said information entity by said subscriber;
d) monitoring a logic state of said serial bus with each of said subscribers during said bus monitoring time period (TU) thereof at a monitoring rate sufficiently high so that receipt of one of said information entities is immediately detected during receipt of said start bit (Sta) of said information entity so detected, said start bit (Sta) being transmitted at said common transmission rate;
e) each of said subscribers (ECU1 to ECU4) determining a state of said flag after expiration of said bus monitoring time period (TU) for said subscriber determining said state of said flag; and
f) only transmitting said information entities from one of said subscribers if said subscriber does not detect that said flag is set during said bus monitoring time period (TU) of said subscriber.
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Accused Products
Abstract
The process for serially transmitting information entities over a serial bus between subscribers (ECU1 to ECU4) at a common transmission rate for all subscribers, includes providing the information entities with a start bit (Sta) at a beginning of transmission of each of the information entities; waiting to transmit the information entities on the bus from each subscriber until after a bus monitoring time period (TU) assigned to each subscriber has elapsed; setting a flag after a subscriber receives one of the information entities; monitoring a logic state of the serial bus during a bus monitoring time period (TU) at a monitoring rate sufficiently high so that receipt of each information entity is detected during reception of a start bit (Sta); each subscriber determining the state of the flag after expiration of the bus monitoring period (TU); and only then transmitting the information entities from the subscriber if the subscriber does not detect that the flag is set during the bus monitoring time period (TU).
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Citations
12 Claims
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1. Process for serially transmitting information entities over a serial bus between a plurality of subscribers (ECU1 to ECU4) connected to said serial bus at a common transmission rate for all of said subscribers, each of said subscribers transmitting said information entities at said common transmission rate, said process comprising the steps of:
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a) providing each of said information entities with a start bit (Sta), said start bit (Sta) being transmitted on said serial bus at a beginning of transmission of each of said information entities; b) prior to transmitting said information entities on said serial bus each of said subscribers transmitting said information entities waits a predetermined bus monitoring time period prior to said transmitting; c) setting a flag after one of said subscribers (ECU1 to ECU4) receives one of said information entities, said flag being set indicating receipt of said information entity by said subscriber; d) monitoring a logic state of said serial bus with each of said subscribers during said bus monitoring time period (TU) thereof at a monitoring rate sufficiently high so that receipt of one of said information entities is immediately detected during receipt of said start bit (Sta) of said information entity so detected, said start bit (Sta) being transmitted at said common transmission rate; e) each of said subscribers (ECU1 to ECU4) determining a state of said flag after expiration of said bus monitoring time period (TU) for said subscriber determining said state of said flag; and f) only transmitting said information entities from one of said subscribers if said subscriber does not detect that said flag is set during said bus monitoring time period (TU) of said subscriber. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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- 8. Control device comprising a microprocessor, a serial bus over which information entities are serially transmitted, at least one serial data device connected to the serial bus and having means for setting a definite transmission rate over said serial bus, means for providing each of said information entities with a start bit to begin transmission of said information entity, means for waiting a bus monitoring time period prior to transmission of said information entities over said serial bus, means for setting a flag to signal reception of one of said information entities thereby, means for monitoring said serial bus during said bus monitoring time period at such a high rate that receipt of said information entities is already detected during receipt of said start bit which is sent at said definite predetermined data transmission rate, means for determining a state of said flag after expiration of the bus monitoring time period, and means for transmitting said information entities on said serial bus only when said flag is not set during said bus monitoring time.
Specification