#32 Automatic Operation of RTC/CTS


I'm using pyserial library to control a /dev/ttyS0 port in linux (Debian), and I need to communicate with an external device that require the hardware handshaking (RTS/CTS).
I'm activating corresponding parameters (rtscts=1, timeout=None) but RTS signal doesn't rise automatically when data must be send, neither down automatically when data was sent. So, I do that manually with timers and functions setRTS(1) / setRTS(0). But this way has many sinchronization issues (cutting frecuently input and/or output messages).
Could you help me, please, telling me what must be done for RTS signal operate unassisted (automatically) ?
Thanks a lot ... pomaresj


  • Chris Liechti

    Chris Liechti - 2010-05-21

    with rtscts=True, the RTS line should be operated automatically, however it works slightly different that you expect. The RTS line will be "active" while the PC is ready to receive data. It will set RTS to "inactive" only when the input buffer gets full. Similarly the PC only sends data when the CTS input is "active" and suspend transmission if CTS is "inactive" (indicating that the other parts receive buffer is full).

  • Chris Liechti

    Chris Liechti - 2010-07-21
    • status: open --> pending
  • SourceForge Robot

    • status: pending --> closed
  • SourceForge Robot

    This Tracker item was closed automatically by the system. It was
    previously set to a Pending status, and the original submitter
    did not respond within 14 days (the time period specified by
    the administrator of this Tracker).


Log in to post a comment.