even paraty setup

edited September 2011 in Propeller 1 Vote Up0Vote Down
Hi

I always use the Fullduplex.spin for serial comunication. It is working fine. Now I need to interface to a device that has specification 2400,8,E,1.

The baud rate is not a problem to set up.

How do I specify the E (Even parity)??

Stef

Comments

  • 9 Comments sorted by Votes Date Added
  • edited September 2011 Posts: 0Vote Up0Vote Down
    Hi Stef

    Search for "FD_Serial_Conf.spin" in the forum, this object should do what you want.

    Andy
  • edited September 2011 Posts: 0Vote Up0Vote Down
    You can use FullDuplexSerial by computing the parity yourself and adding it into the 8-bit value you're sending. For transmitting a 7-bit character CH with even parity, do:
    FDS.tx((CH & %1111111) | (((CH<<1) ^ (CH<<2) ^ (CH<<3) ^ (CH<<4) ^ (CH<<5) ^ (CH<<6) ^ (CH<<7) ^ %10000000) & %10000000))
    On receive, you'd do a similar calculation, but compare the result with what was actually received.
  • edited September 2011 Posts: 169Vote Up0Vote Down
    Tanks to all

    I'm going to try it out.

    Stef
  • edited September 2011 Posts: 0Vote Up0Vote Down
    Wait a mintute. I thought 8,E,1 meant 8 Data bits plus 1 parity bit plus 1 stop bit. So putting the parity bit into the top bit of the 8 bits of data does not do what you want.
  • edited September 2011 Posts: 0Vote Up0Vote Down
    I think 8, E means 8 bits including even parity, 8+parity would mean 9 bits...
  • edited September 2011 Posts: 0Vote Up0Vote Down
    Ok. I'm confused. If the parity bit is in the 8 data bits would that not really be 7 data bits plus 1 parity bit or "7,E,1"?
  • edited September 2011 Posts: 0Vote Up0Vote Down
    Heater is right. 2400,8,E,1 would be 2400 baud, 1 start bit, 8 data bits, 1 even parity bit, and 1 stop bit for a total of 11 bits.
    In science there is no authority. There is only experiment.
  • edited September 2011 Posts: 0Vote Up0Vote Down
    "For example, a frame that uses seven data bits, even parity, and one stop bit is abbreviated 7E1, and one that uses eight data bits, no parity, and one stop bit is abbreviated 8N1."

    http://www.freeopenbook.com/pc-hardware-nutshell-2/pchardnut2-CHP-22-SECT-1.html
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