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3 wire serial connection to BasicStamp? — Parallax Forums

3 wire serial connection to BasicStamp?

ArchiverArchiver Posts: 46,084
edited 2003-05-13 12:54 in General Discussion
Can I use only the Rx, Tx and GND lines to connect a PC to the BS2p?
Can I somehow avoid connecting the DTR line to ATN pin on the BS2p?
i.e. Can I use someother circuitry on the board where I use the BS2p
and avoid having an extra line going to the PC for serial connection?
Thanks a lot

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2003-05-08 18:53
    You CAN leave out the DTR pin, but if you do
    you won't be able to program the BS2P in-circuit.
    (that's what the IDE uses to reset and prepare
    the chip for download). Plus, the only
    use for the ATN pin on the BS2 is to reset the
    chip, so you can't re-use the pin on the module.

    Since this pin already has all the 232 driver
    circuitry it needs, the only savings you get
    is one wire -- which seems trivial compared to
    all the functionality you lose.

    So, if you don't want to program the chip, and
    you really want to have just three wires
    (RX, TX, and GND) connected, then yes, your
    'target' board does not require DTR connected.
    It's not needed (to my knowledge) for run-only
    use of the BS2. You'll probably have to tie
    ATN low, in that case, through a 10Kohm resistor.

    --- In basicstamps@yahoogroups.com, "mohammedrasiq"
    <mohammedrasiq@y...> wrote:
    > Can I use only the Rx, Tx and GND lines to connect a PC to the BS2p?
    > Can I somehow avoid connecting the DTR line to ATN pin on the BS2p?
    > i.e. Can I use someother circuitry on the board where I use the
    BS2p
    > and avoid having an extra line going to the PC for serial
    connection?
    > Thanks a lot
  • ArchiverArchiver Posts: 46,084
    edited 2003-05-08 19:04
    http://www.qsl.net/kf4haz/cables/stamps/

    From: "mohammedrasiq" <mohammedrasiq@
    > Can I use only the Rx, Tx and GND lines to connect a PC to the BS2p?
    > Can I somehow avoid connecting the DTR line to ATN pin on the BS2p?
    > i.e. Can I use someother circuitry on the board where I use the BS2p
    > and avoid having an extra line going to the PC for serial connection?
    > Thanks a lot
  • ArchiverArchiver Posts: 46,084
    edited 2003-05-13 12:54
    you can actually connect the stamp to the pc with only two lines for one way
    data transfer or three lines for bi-directional with no handshaking.
    (2,3,5)

    Jim
    http://www.geocities.com/jimforkin2003/

    Original Message
    From: mohammedrasiq [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=TYTa9Nt--PJurE22S8reZgWwDDEm9ktTx7WNY4-QkT6dWdfU_E4otV08_ITFetdYrLsGFS1r7-5op5ONZYE]mohammedrasiq@y...[/url
    Sent: Thursday, May 08, 2003 12:15 PM
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] 3 wire serial connection to BasicStamp?


    Can I use only the Rx, Tx and GND lines to connect a PC to the BS2p?
    Can I somehow avoid connecting the DTR line to ATN pin on the BS2p?
    i.e. Can I use someother circuitry on the board where I use the BS2p
    and avoid having an extra line going to the PC for serial connection?
    Thanks a lot



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