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FTDI cts and rts pins — Parallax Forums

FTDI cts and rts pins

BitsBits Posts: 414
edited 2012-04-17 09:42 in Propeller 1
I wanted to know if I can directly tie the FTDI pins (CTS and RTS) to the propeller without using a pull up / pull down resistor? I ask this because I think that at some point I attempted to do just this and the propeller would not accept code from the compiler. I intend on using the FTDI ic for programming the propeller and communications to the computer.

Thanks in advance.

Comments

  • RaymanRayman Posts: 14,839
    edited 2012-04-17 09:42
    Well, the FT232RL can be run with either 5V or 3.3V I/O. So, I'll assume you'll have it in the 3.3V I/O configuration.
    Then, RTS is an output of FT232RL and CTS is an input. CTS has an internal pullup, so you don't need to have one.
    RTS is an output, so it doesn't need one either.
    I usually leave both of these pins not connected.
    One issue you may face is the FT232 powerup and reboot problem. This occurs if the FT232 has no power, but is connected to a Propeller pin in the high state.
    The Propeller slowly powers up the FT232 chip (probably through it's internal pullup resistor) and then it wakes up and resets the Prop...
    So, you might want to consider some 10k series resistors to prevent that...
    (this same thing applies to RX and TX).
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