Z-World Wolf BL2600 User Manual - page 24

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Wolf (BL2600)

3.3  Serial Communication

The BL2600 has three serial communication ports, which can be configured as one RS-232 

serial channel (with RTS/CTS) and one RS-232 (3-wire) channel or one RS-485 channel, or 

as three RS-232 (3-wire) channels, or as two RS-232 (3-wire) channels and one RS-485 

channel by using the 

serMode

 software function call. Table 6 summarizes the options.

The BL2600 also has one CMOS serial channel that serves as the programming port.

All four serial ports operate in an asynchronous mode. An asynchronous port can handle 7 

or 8 data bits. A 9th bit address scheme, where an additional bit is sent to mark the first 

byte of a message, is also supported. Serial Port A, the programming port, can be operated 

alternately in the clocked serial mode. In this mode, a clock line synchronously clocks the 

data in or out. Either of the two communicating devices can supply the clock. The BL2600 

boards typically use all four ports in the asynchronous serial mode. Serial Ports C and F 

are used for RS-232 communication, and Serial Port E is used for RS-232 or RS-485 com-

munication. The BL2600 uses a 22.12 MHz resonator, which is doubled to 44.2 MHz. At 

this frequency, the BL2600 supports standard asynchronous baud rates up to a maximum 

of 5.525 Mbps. 

3.3.1  RS-232

The BL2600 RS-232 serial communication is supported by an RS-232 transceiver. This 

transceiver provides the voltage output, slew rate, and input voltage immunity required to 

meet the RS-232 serial communication protocol. Basically, the chip translates the Rabbit 

3000’s CMOS signals to RS-232 signal levels. Note that the polarity is reversed in an 

RS-232 circuit so that a +3.3 V output becomes approximately -10 V and 0 V is output as 

+10 V. The RS-232 transceiver also provides the proper line loading for reliable commu-

nication.

RS-232 can be used effectively at the BL2600’s maximum baud rate for distances of up to 

15 m.

3.3.2  RS-485

The BL2600 can be set for one RS-485 serial channel, which is connected to the Rabbit 

3000 Serial Port E through an RS-485 transceiver. The half-duplex communication uses 

the Rabbit 3000’s PE3 pin to control the transmit enable on the communication line.

Table 6.  Serial Communication Configurations

Mode

Serial Port

C

E

F

0

RS-232, 3-wire

RS-232, 3-wire

RS-232, 3-wire

1

RS-232, 3-wire

RS-485

RS-232, 3-wire

2

RS-232, 5-wire

RS-232, 3-wire

CTS/RTS

3

RS-232, 5-wire

RS-485

CTS/RTS