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start and stop bits — Parallax Forums

start and stop bits

Spork FrogSpork Frog Posts: 212
edited 2007-04-04 13:43 in Propeller 1
When using the FTDI usb-to-serial devices, do you need to use start and stop bits? If so, should these be high or low?

I've been trying unsuccessfully to make a serial communications program with my Hydra.

Comments

  • QuattroRS4QuattroRS4 Posts: 916
    edited 2007-04-04 04:36
    LarryHedgehog,
    Not quite sure what you are asking here - can you give a bit more detail ...


    Quattro

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    'Necessity is the mother of invention'

    Post Edited (QuattroRS4) : 4/4/2007 5:02:22 AM GMT
  • Mike GreenMike Green Posts: 23,101
    edited 2007-04-04 04:51
    All asynchronous serial devices by definition use start and stop bits and the FTDI usb-to-serial adapters are no exception. The start bit is always a zero and the stop bit is always a one. The FTDI devices use 0V for a zero and +3.3V (or +5V for some adapters) for a one. This is "true" mode. "inverted" mode is the opposite and is normally used when going through a device like the MAX3232 which includes an inverter.
  • Spork FrogSpork Frog Posts: 212
    edited 2007-04-04 12:19
    Ahh.. okay. So I also assums that the line should be held high when no data is being transferred?
  • Mike GreenMike Green Posts: 23,101
    edited 2007-04-04 13:43
    Yes, the line should be idling at high
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