101-0898 Rabbit Semiconductor, 101-0898 Datasheet - Page 107

• Manufacturer Part Number: 101-0898
• Description: KIT WEB SECURE EMBEDDED RCM3700
• Manufacturer: Rabbit Semiconductor
• Series: RabbitCore 3000r

Specifications of 101-0898

• Main Purpose: Interface, Ethernet
• Utilized Ic / Part: RCM3700
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Secondary Attributes: -
• Embedded: -
• Primary Attributes: -
• Other names: 101-898; 101-898

B.1.6.2 RS-485
The RCM3700 Prototyping Board has one RS-485 serial channel, which is connected to
the Rabbit 3000 Serial Port E through an RS-485 transceiver. The half-duplex communi-
cation uses an output from PF5 on the Rabbit 3000 to control the transmit enable on the
communication line. Using this scheme a strict master/slave relationship must exist
between devices to insure that no two devices attempt to drive the bus simultaneously.
Serial Port E is configured in software for RS-485 as follows.
The configuration shown above is based on circular buffers. RS-485 configuration may
also be done using functions from the
The RCM3700 Prototyping Boards with RCM3700 modules installed can be used in an
RS-485 multidrop network spanning up to 1200 m (4000 ft), and there can be as many as
32 attached devices. Connect the 485+ to 485+ and 485– to 485– using single twisted-pair
wires as shown in Figure B-8. Note that a common ground is recommended.
RabbitCore RCM3700 User’s Manual
#define ser485open serEopen
#define ser485close serEclose
#define ser485wrFlush serEwrFlush
#define ser485rdFlush serErdFlush
#define ser485putc serEputc
#define ser485getc serEgetc
#define EINBUFSIZE
#define EOUTBUFSIZE 15
Figure B-8. RCM3700 Multidrop Network
15
PACKET.LIB
library.
105