CAN Bus 5 (Preference)
|Unequal amounts of data per message.|
The data packages which are transmitted over the same Bus may differ in length, in spite of just one start bit and (almost) always 11 precedence bits. The ensuing data, placed third, is the only part of the total package
which may differ in terms of length. The length of the data package is defined in the control field. This is a one bit block at the beginning of the data package.
|Stuff bits may not be accounted for.|
By the way, you should be careful when analyzing the single bits to recognize the stuff bits. These are changes of the voltage which must be inserted after the same bits have been used five times in a row. This is
necessary for the clocks (timer) inside the Bus participants to synchronize again. Thus, after five zero bits there is a one bit and vice versa. The stuff bit may not be counted. You see an example of such a bit on top in
the picture. After the same five bits in the middle the next one is not taken into account when analyzing the message.
|Controller Area Network Bus without master or slave, easy to complement|
There is neither a master nor a slave for the Controller Area Network Bus. The control devices are not prioritized, but the messages are. An existing Controller Area Network Bus can be easily adapted to new
messages or transmitters / receivers. Gaps in between the Identifiers make it even easier. However, the list of messages to be received or dispatched has to exactly fit in with those of the new subscribers in the Bus.
In any case, you should not forget to register supplemental functions / hardware, e.g., in the central control device. Also the lists of the affected subscribers must be complemented accordingly. Indeed, everything
except for the actual clamping on of the new subscriber comprises just a software change. 05/07