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Odd Parity for BS2? — Parallax Forums

Odd Parity for BS2?

ArchiverArchiver Posts: 46,084
edited 2001-09-09 15:00 in General Discussion
Regarding my Question about the RS-232 interface:

I been reading some information on the internet and I found this:

"The EIA-232 spec provides for both sync and async but PC's use a UART
(Universal Asynchronous Receiver/Transmitter) chip such as a 16450, 16550A, or
16650 and can't deal with sync."

But I can control the video camera using software on a PC computer with a 9-pin
Com port.
Even if the specification says syncron transfer.
Could it be a typing error in the specification for the communication protocol?
I used another computer to listen to the communication between the computer
running the software and the camera. The two commands that I wish to build-in
to my controller is only 3 byte long. Can I somehow make the Basic Stamp "say"
a string of ones and zeros to control the camera (adding start/stop bit & and 1
odd parity bit manually)?
I don't need to get an answer from the camera.

Or, can I get the basic stamp to use odd parity somehow?
Can I get Odd parity with any of the basic stamps?

Please help me!

Best regards

Johan Brostrom


[noparse][[/noparse]Non-text portions of this message have been removed]

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2001-09-09 04:33
    On 8 Sep 01 at 21:19, Johan Brostrom wrote:

    > The two commands that I wish to build-in to my controller
    > is only 3 byte long. Can I somehow make the Basic Stamp "say" a
    > string of ones and zeros to control the camera (adding start/stop
    > bit & and 1 odd parity bit manually)? I don't need to get an answer
    > from the camera.

    Exactly what is the stream of bytes you must send, and what is the
    slowest transmission (baud) rate your camera will accept? There may
    be a way to get there from here...

    Regards,

    Steve
  • ArchiverArchiver Posts: 46,084
    edited 2001-09-09 15:00
    >
    > Regarding my Question about the RS-232 interface:
    >
    > I been reading some information on the internet and I found this:
    >
    > "The EIA-232 spec provides for both sync and async but PC's use a UART
    > (Universal Asynchronous Receiver/Transmitter) chip such as a 16450, 16550A, or
    > 16650 and can't deal with sync."
    Must be an asynchronous then, the DB25 pinout had pins defined for the
    Clock for synchronous devices.
    > But I can control the video camera using software on a PC computer with a
    9-pin
    > Com port. Even if the specification says syncron transfer. Could it be a
    typing
    > error in the specification for the communication protocol? I used another
    > computer to listen to the communication between the computer running the
    > software and the camera. The two commands that I wish to build-in to my
    > controller is only 3 byte long. Can I somehow make the Basic Stamp "say" a
    > string of ones and zeros to control the camera (adding start/stop bit & and 1
    > odd parity bit manually)? I don't need to get an answer from the camera.
    Doesn't look like any do odd, even in 8 bit mode. If you could get the timing
    right, you might be able do toggle the pin after the serout command.
    Anoter possiblity is the Maxim SPI UART, but I don't know if it will do 8 bits
    plus parity.
    > Or, can I get the basic stamp to use odd parity somehow?
    > Can I get Odd parity with any of the basic stamps?
    >
    > Please help me!
    >
    > Best regards
    >
    > Johan Brostrom
    >
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