B.4.6.2 RS-485
The Prototyping Board has one RS-485 serial channel, which is connected to the Rabbit
3000 Serial Port C through an RS-485 transceiver. The half-duplex communication uses
an output from PD7 on the Rabbit 3000 to control the transmit enable on the communica-
tion 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 C is configured in software for RS-485 as follows.
#define
#define
#define
#define
#define
#define
ser485open serCopen
ser485close serCclose
ser485wrFlush serCwrFlush
ser485rdFlush serCrdFlush
ser485putc serCputc
ser485getc serCgetc
#define CINBUFSIZE 15
#define COUTBUFSIZE 15
#ifndef _485BAUD
#define _485BAUD 115200
#endif
The configuration shown above is based on circular buffers. RS-485 configuration may
also be done using functions from the PACKET.LIB library.
The Prototyping Boards with RCM3360/RCM3370 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.
Figure B-8. Multidrop Network
88
RabbitCore RCM3360/RCM3370
相关PDF资料
101-1050-BE-00025 ADPT USB 2 A FEMALE-2 5PIN .25M
10112627-101LF MINI-SAS HD 1X2 EXT PCB
10112628-101LF MINI-SAS HD 1X4 EXT PCB
10136-3000PC CONN MINI-D 36POS SOLDER PLUG
10136-6000EC CONN MDR PLUG 36POS IDC GOLD
10150-4CZ3PL CONN MDR PLUG 50POS VERT T/H
10150-72E2PC CONN MINI-D 50POS R/A PLUG
10150-8000EE CONN PLUG 50 POS MINI-D
相关代理商/技术参数
101-0955 功能描述:模块化系统 - SOM RCM2260 RABBITCORE MODULE RoHS:否 制造商:Digi International 外观尺寸:ConnectCore 9P 处理器类型:ARM926EJ-S 频率:150 MHz 存储容量:8 MB, 16 MB 存储类型:NOR Flash, SDRAM 接口类型:I2C, SPI, UART 工作电源电压:3.3 V 最大工作温度:+ 85 C 尺寸:1.97 in x 1.97 in x 6.1 in
101-0956 功能描述:开发板和工具包 - 其他处理器 Powercore Flex Kit US Version RoHS:否 制造商:Freescale Semiconductor 产品:Development Systems 工具用于评估:P3041 核心:e500mc 接口类型:I2C, SPI, USB 工作电源电压:
101-0957 功能描述:开发板和工具包 - 其他处理器 Powercore Flex Kit International Vers. RoHS:否 制造商:Freescale Semiconductor 产品:Development Systems 工具用于评估:P3041 核心:e500mc 接口类型:I2C, SPI, USB 工作电源电压:
101-0961 功能描述:模块化系统 - SOM RCM3720 CORE MOD. RoHS:否 制造商:Digi International 外观尺寸:ConnectCore 9P 处理器类型:ARM926EJ-S 频率:150 MHz 存储容量:8 MB, 16 MB 存储类型:NOR Flash, SDRAM 接口类型:I2C, SPI, UART 工作电源电压:3.3 V 最大工作温度:+ 85 C 尺寸:1.97 in x 1.97 in x 6.1 in
10-109611-3S 制造商:Amphenol Corporation 功能描述:10-109611-03S - Bulk
10-109611-4S 制造商:Amphenol Corporation 功能描述:10-109611-04S - Bulk
10-109614-02S 制造商:Amphenol Corporation 功能描述:ER 4C 4#16S SKT PLUG
10-109614-05P 制造商:Amphenol Industrial Operations 功能描述:ER 5C 5#16S PIN PLUG