Using MSP430F149 with FSK modem for Hart Protocol

Discussion in 'Embedded Systems and Microcontrollers' started by ecn113, Jun 20, 2007.

  1. ecn113

    Thread Starter New Member

    Jun 20, 2007
    2
    0
    Trying to integrate HART protocol into a sensor design that uses the MSP430 as the microcontroller. I am using an FSK modem to modulate/demodulate the signal from the micro to the 4-20mA analog line. According to my research I will eventually have to configure the micro by programming the universal asynchronous receiver transmitter (UART) to receive and transmit 11 bit (includes start, stop, and parity bit) in a half-duplex manner. The MSP430F149 have two UARTs (UART0 & UART1). I was wondering if it is going to be easier to program one to receive and the other to transmit to avoid data collision. I was going to try to use IAR workbench to flash the micro and hyperterminal to test communication but am unsure if this will work. Any suggestions would be helpful
     
  2. Papabravo

    Expert

    Feb 24, 2006
    10,144
    1,791
    If the serial port is half duplex there is no reason to use the second UART. The hardware is there to do everything you need to do. One question though: who decides which way the serial line is going?
     
  3. ecn113

    Thread Starter New Member

    Jun 20, 2007
    2
    0
    The programming on the UART will decide when all bits have been recieved or when all bits have been transmitted by setting a flag of some sort. The bit lenght is known and a start and stop bit is used. This is part of the project I am trying to develop right now.
     
  4. Papabravo

    Expert

    Feb 24, 2006
    10,144
    1,791
    You did not answer my question. The answer you gave leads me to believe that you are not familiar with the terms half-duplex and full-duplex. Let me elaborate. In a half-duplex situation there is only one signal line used for transmitting and receiving data. If there are two or more transmitters connected together then there must be a mechanism to determine which transmitter has the right to speak.

    In a full duplex system there is a transmit data line and a receive data line and transmission and reception can happen simultaneously. I'm not that familiar with HART, so if you could give me a link to the HART specification it would help me to help answer your questions.
     
Loading...