Manufacturer Specific Profile Area
Manual • Doc.-No.: C.3055.21 / Rev. 1.1
CAN-CBX-COM2
Page 104 of 125
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Explanation to the Multidrop Mode:
Via the bits of the parameter Serial_Mode the multidrop mode can be chosen (see
table 24).
The multidrop mode can be used for RS-485 networks with multipoint structure. For
this the RTS-Mode bit has to be set to 1 and the following bits are as described in the
following table.
Bit
7
6
5
4
3
2
1
0
Assignment
RTS-
Mode
CTS-
enable
Stop-Bit
Parity-Mode
Parity-
Type
Bits per Character
Default
1
-
-
1
0
1
1
1
Table 30: Assignment of the parameter Serial_Mode for the multidrop mode
The multidrop mode can be used for RS-485 networks with multipoint structure.
In this network there is one master and several slaves on a serial bus:
Fig. 26: Structure of a multipoint bus
An addressing is necessary for the distinction of the slaves. The paritity bit is turned
into an ‘address-bit’ in the multidrop mode to distinguish the address information
from the data. For paritity bit set to ‘1’ the received data are to interpret as address.
For paritity bit set to ‘0’, it is process data.
Fig. 27: Structure of the Tx-data in multidrop mode