TSS461F datasheet(46/57 Pages) ATMEL

46 / 57 page

7615A–AUTO–02/06

TSS461F

•

Failure cases:- Code viol (CV error bit)

–

Acknowledge error (ACKE error bit)

–

CRC error (FCSE error bit)

•

It should be noticed that contention is considered as normal CSMA/CD protocol and,

therefore, is not taken into account in failure cases. So, an 'infinite' number of attempts can

be performed if bus contention occurs continuously.

There is only one retries counter for all channels. When the user writes the Max_Retries value,

all channels start their transmission with this parameter.

Rearbitrate

The purpose of rearbitrate feature is to postpone a channel already in transmission in order to

authorize an higher priority (see section “Priority Among the Different Channels”) message to be

transmit.

Typical Example

•

Max_retries = 1 (2 transmissions attempts).

•

If Ch 8 is in a the retry loop and the user wants to transmit the Ch 5 without waiting the end

of the loop, the user can use the rearbitrate command.

•

Then, the TSS461F will wait the end of the current transmission, reload the retries counter

and enable the Ch 5 to transmit.

•

At the end of this transmission Ch5, either when the attempt is successful or either when the

exceeded retry count is reached, the retries counter is reloaded and the transmission is

activated for the Ch 8 again.

Figure 26. Rearbitrate Example

EOF+IFS

Delay

stand-by

Delay

Viol

EOF+IFS: 8 + 4 Timeslots

Delay Viol: 12 Timeslots

* (not seen by application means no IT

generation)

TSS461F Datasheet(PDF) 46 Page - ATMEL Corporation