disable TX

hi,

is there any way of enabling/disabling the TX pin?
In some cases, I need to send the data only through the USB and disable the TX, while in other cases to send the data through the TX (in baud rate that is not supported by the USB drivers).

thanks,
w

Not from software. The TX pin on the Arduino board and the FTDI chip that does the USB communication are both connected to the same pin on the ATmega168. You can disable it, but then the communication won’t go to either place.

while in other cases to send the data through the TX (in baud rate that is not supported by the USB drivers).

Do you care if the FTDI sees the signal?

If you don’t, you could share the TX on both serial interfaces, just that the FTDI won’t recognize it.

If you don’t, you could share the TX on both serial interfaces, just that the FTDI won’t recognize it.

well, ideally i would like to completely disable the TX when thr FDTI is used. I use the TX for MIDI out and the TDFI for serial. So, if I use the FTDI while have a MIDI device conneceted to TX, the MIDI device will still accept random messages…

But I guess it’s not possible from software as mellis said. :frowning: anyway…

thanks for your help
w

If you’re going the hardware route, maybe consider a level shifter/buffer with an output enable.

hi AVRman,

seems like I’ll have to go the hardware route…

thanks for your advice. I’ll have a look to “a level shifter/buffer with an output enable” option,
although I’m not sure what exactly is that… :slight_smile:

hi AVRman,

seems like I’ll have to go the hardware route…

thanks for your advice. I’ll have a look to “a level shifter/buffer with an output enable” option,
although I’m not sure what exactly is that… Smiley

I used one of these 5-pin devices once (74HVC family), you might be able to dig around for it in a DIP package that’s easier to work with,
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=MC74VHC1GT125OSCT-ND

Pins:
In
Out
+5v
Gnd
Output Enable (active low)

thanks