Pro II: Extension and Interface Modules
Pro II-RSxxx Rev. E
ADwin
172
ADwin-Pro II
Hardware, manual Dec. 2018
Interface parameters
Each interface has an input and an output FIFO with a length of 64 bytes each.
The settings of the interface parameters are made separately for each chan-
nel, using the controller register. Below the settings are described more
detailed:
Handshake
– Handshake: The interface can be operated in 3 modes:
1. Without handshake
2. Software handshake
3. Hardware handshake (RS232 only).
When using the hardware handshake the signals RTS and CTS must
be connected.
Parity
– Parity: In order to recognize an error or incorrect data during the transfer,
a parity bit can be transferred at the same time. The parity can be even
or odd or you can have no parity bit at all.
Data bits
– Data bits: the active data to be transferred may be 5...8 bits long.
Stop bits
– Stop bits: The number of stop bits can be set to 1, 1½ or 2. Here the num-
ber of stop bits depends on the number of data bits:
• 5 data bits: 1 or 1½ stop bits.
• 6…8 data bits: 1 or 2 stop bits.
Baud rate
– Baud rate: The physical data are between 35 Baud and 2.304 MBaud;
when using an RS-232 interface the maximum Baud rate is 115.2kBaud,
according to the specification.
The Baud rates are derived from the clock rate of the module; the basic
clock rate has a frequency of 2.304MHz. Based on this fact, every Baud
rate is possible, which can be derived from an integer division of the ba-
sic frequency. The divisor can have values between
1
…
0FFFFh
. The
following table shows some common Baud rates and their divisors.
Fig. 149 – Pro II-RS-xxx: Baud rates
Special features of RS485
Contrary to the RS232 and RS422 interface, with RS485 more than 2 partici-
pants can communicate with each other. With an RS485 interface, a bus is set
up.
Consider the following:
– There is no handshake, because a handshake is only possible between
two participants.
– The interface must know if it should write to the bus or get data from the
bus (
RS485_SEND
).
Baud rate
Divisor
Baud rate
Divisor
dec.
hex.
dec.
hex.
2.304.000
1
0001h
19.200
120
0078h
1.152.000
2
0002h
9.600
240
00F0h
460.800
5
0005h
4.800
480
01E0h
230.400
10
000Ah
2.400
960
03C0h
115.200
20
0014h
1.200
1920
0780h
57.600
40
0028h
600
3840
0F00h
38.400
60
003Ch
300
7680
1E00h
