Method and apparatus for serial data transmission at a switchable data rate

Abstract

A method and an apparatus are specified in order to allow larger amounts of data to be transmitted relatively quickly in a network. According to the invention, the object is achieved in that the transmitted data frames have a logic structure in accordance with CAN Specification ISO 11898-1, wherein the time bit length within a data frame can assume at least two different values, wherein, for a first predeterminable area within the data frame, the time bit length is greater than or equal to a predetermined minimum value of approximately one microsecond, and in at least one second predeterminable area within the data frame, the time bit length is at least half, and preferably less than half, with respect to the first area, wherein changes in the time bit length are achieved by use of at least two different scaling factors for setting the bus time unit relative to a shortest time unit or the oscillator clock during operation.

Description

technical field [0001] The invention relates to a method and a device for transmitting data between at least two subscribers of a bus system, in which the duration of the transmitted bit can be switched between at least two different values. Background technique [0002] A controller area network and a CAN expansion known as "time-triggered CAN" (TTCAN) are known, for example, from laid-open document DE 100 00 305 A1. The medium access control method used in CAN is based on bit-by-bit arbitration. With bit-by-bit arbitration, several subscriber stations can simultaneously transmit data via the channels of the bus system without thereby interfering with the data transmission. Subscriber stations can also determine the logical state (0 or 1) of the channel when sending bits over the channel. If the value of the transmitted bit does not correspond to the determined logical state of the channel, the subscriber station terminates access to the channel. In CAN, bit-by-bit arbit...

AI Technical Summary

Problems solved by technology

[0008] G.Cena and A.Valenzano theoretically discussed in "Overclocking of controller area networks" (Electronics Letters, Volume 35, Issue 22 (1999), 1924) that the overclocking of the bus frequency is effective in the sub-area of ​​the data frame effect on the achieved data rate, but did not go into details of the method and the different states and state transitions of the bus users

[0009] It is demonstrated from the cited literature that the prior art does not provide satisfactory results in all respects

Images