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SERIN using 9 bit — Parallax Forums

SERIN using 9 bit

ArchiverArchiver Posts: 46,084
edited 2003-11-26 14:34 in General Discussion
Hello,
I'm talking to a sensor using 9 bits RS232 (instead of 8 bits). This
does not include the start and stop bit. I can tell the sensor (for
example):
SEROUT 15,T9600,[noparse][[/noparse]BIN9 %101010101]

But I can't receive the 9 bit "answer" back:
SERIN 14,T9600,2000,NoData,[noparse][[/noparse]BIN9 ANSWER] 'Answer is delcared
as a Word.

It time's out. Any suggestions?
Other notes:
1. My oscope shows a word is coming back-- with plenty of time to
receive (10ms).
2. I'm at the right baud rate

Thanx,
-Barry

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2003-11-25 19:00
    >Hello,
    >I'm talking to a sensor using 9 bits RS232 (instead of 8 bits). This
    >does not include the start and stop bit. I can tell the sensor (for
    >example):
    >SEROUT 15,T9600,[noparse][[/noparse]BIN9 %101010101]

    That sends a string of 9 ascii characters as you would display them
    on a screen, not what you might be expecting, a single unit
    consisting of 9 bits.

    >
    >But I can't receive the 9 bit "answer" back:
    >SERIN 14,T9600,2000,NoData,[noparse][[/noparse]BIN9 ANSWER] 'Answer is delcared
    >as a Word.

    That would only work if the answer is in fact 9 bytes containing the
    ascii string "bbbbbbbbb". So if the system only answers back with
    one 9-bit code, then SERIN will time out waiting for the other 8
    bytes.


    >
    >It time's out. Any suggestions?


    The Stamp cannot do 9 bit SERIN nor 9 bit SEROUT. The only options
    are 8 bits, no parity, or 7 bits, even parity. To send and receive 9
    bits you would have to go to an external UART, like the MAX3100
    series from Maxim-ic.

    >Other notes:
    >1. My oscope shows a word is coming back-- with plenty of time to
    >receive (10ms).
    >2. I'm at the right baud rate
    >
    >Thanx,
    >-Barry


    Is this for your Prius?

    -- Tracy
  • ArchiverArchiver Posts: 46,084
    edited 2003-11-26 14:34
    It's an honor hearing from you. I've studied some of your Stamp work.
    I'll try the UART.
    This is not for my Prius (this time).
    -Barry

    --- In basicstamps@yahoogroups.com, Tracy Allen <tracy@e...> wrote:
    > >Hello,
    > >I'm talking to a sensor using 9 bits RS232 (instead of 8 bits).
    This
    > >does not include the start and stop bit. I can tell the sensor (for
    > >example):
    > >SEROUT 15,T9600,[noparse][[/noparse]BIN9 %101010101]
    >
    > That sends a string of 9 ascii characters as you would display them
    > on a screen, not what you might be expecting, a single unit
    > consisting of 9 bits.
    >
    > >
    > >But I can't receive the 9 bit "answer" back:
    > >SERIN 14,T9600,2000,NoData,[noparse][[/noparse]BIN9 ANSWER] 'Answer is delcared
    > >as a Word.
    >
    > That would only work if the answer is in fact 9 bytes containing
    the
    > ascii string "bbbbbbbbb". So if the system only answers back with
    > one 9-bit code, then SERIN will time out waiting for the other 8
    > bytes.
    >
    >
    > >
    > >It time's out. Any suggestions?
    >
    >
    > The Stamp cannot do 9 bit SERIN nor 9 bit SEROUT. The only options
    > are 8 bits, no parity, or 7 bits, even parity. To send and receive
    9
    > bits you would have to go to an external UART, like the MAX3100
    > series from Maxim-ic.
    >
    > >Other notes:
    > >1. My oscope shows a word is coming back-- with plenty of time to
    > >receive (10ms).
    > >2. I'm at the right baud rate
    > >
    > >Thanx,
    > >-Barry
    >
    >
    > Is this for your Prius?
    >
    > -- Tracy
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