Rabbit RabbitCore RCM4200 User Manual

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Rabbit RabbitCore RCM4200 User Manual Manual pdf 41 page image

User’s Manual 354.2 Serial CommunicationThe RCM4200 module does not have any serial driver or receiver chips directly on theboard. However, a serial interface may be incorporated on the board the RCM4200 ismounted on. For example, the Prototyping Board has an RS-232 transceiver chip.4.2.1 Serial PortsThere are five serial ports designated as Serial Ports A, B, C, D, and E. All five serial portscan operate in an asynchronous mode up to the baud rate of the system clock divided by 8.An asynchronous port can handle 7 or 8 data bits. A 9th bit address scheme, where anadditional bit is sent to mark the first byte of a message, is also supported.Serial Port A is normally used as a programming port, but may be used either as an asyn-chronous or as a clocked serial port once application development has been completed andthe RCM4200 is operating in the Run Mode.Serial Port B is shared by the RCM4200 module’s A/D converter, and is set up as aclocked serial port. Since this serial port is set up for synchronous serial communicationon the RCM4200 model, you will lose the A/D converter’s functionality if you try to usethe serial port in the asynchronous mode. Serial Port B is available without any restrictionson the RCM4210.Serial Port C is shared with the serial flash, and is set up as a clocked serial port. PE7 is setup to provide the SCLKC output to the serial flash, but PD2 also provides the SCLKCouput automatically when Serial Port C is used as a clocked serial port. Since this serialport is available for synchronous serial communication on either RCM4200 model, youwill lose the serial flash’s functionality if you try to use the serial port in the asynchronousmode.NOTE: Since Serial Port C is shared with the serial flash, exercise care if you attempt touse Serial Port C for other serial communication. Your application will have to managethe sharing negotiations to avoid conflicts when reading or writing to the serial flash.Serial Port D may also be used as a clocked serial port. Note that PD0 provides theSCLKD ouput automatically when Serial Port D is set up as a clocked serial port.Serial Port E, which is available only on the RCM4210, can also be configured as anSDLC/HDLC serial port. The IrDA protocol is also supported in SDLC format by SerialPort E. Serial Port E must be configured before it can be used. The sample programIOCONFIG_SWITCHECHO.C in the Dynamic C SAMPLES\RCM4200\SERIAL foldershows how to configure Serial Port E.