Clipping the 5v header pin for the FTDI

Projects General Guidance
1

I use the ArduinoDroid IDE on an Android tablet with a USB cable to a FTDI to upload sketches to a bread-boarded 328.

The 328 is powered by a 5v wall wart...that I unplug prior to uploading a new sketch.

Sometimes the tablet (via FTDI) is apparently unable to power the board and peripherals (SD card, LCD, and more...): the LCD goes black and the upload fails.

I'm thinking of leaving the wall wart plugged in during uploads, but first clipping the 5v pin on the FTDI header (so the two power sources won't fight). The power sources will share a common ground via the FTDI's ground pin.

I can't think of any reason why this shouldn't work or might cause problems.

Would appreciate some comments before I try it.

Thank you,
Dave

2

but first clipping the 5v pin on the FTDI header

Or bending the pin 90'

What Arduino board do you have?

3

none - it's just a 328 chip with caps, xtal, etc. Set up like this, minus the LEDs, plus the peripherals.

Yes - or bending it 90 deg...

4

When I use Arduino Pro Minis I remove the FTDI +5 volt pin.

5

Cool - thanks!

6

Can you put a second header on the breadboard with the power pin missing?
That way you won't need to damage the FTDI connector.

On a board I made recently I put a little jumper that I can remove before I connect the Pro-Micro to the USB cable so that the external power supply no longer powers the Arduino.

...R

7

I wasn't thinking of modding the FTDI itself. I have six pin (male) header attached to the breadboard; the FTDI (with female connectors) attaches to it. I was just going to snip (or bend) the power pin of the male header.

8

Why not make a small M-F cable without the power connected? This way, you wouldn't have to modify either the FTDI or your circuit/connection.

--Doug

9

DaveEvans:
I wasn't thinking of modding the FTDI itself.

That makes sense. But it is not the message that your Title conveys.

...R

10

I'm sorry you found it ambiguous or misleading. I appreciate the time you spend helping folks like me on this forum.

11

I forgot to say that another useful option is a header that does not have a Reset connection. That allows you to connect the FTDI cable and see what the Arduino is sending to the Serial Monitor without causing the Arduino to reset.

...R

12

Hmm - good idea - thanks again!