Arduino, FTDI and extra VCC - How to connect?

I have an Arduino Pro mini which is connected to an FTDI (FTD232).
The Arduino has a number of peripherals using a number of GPIOs.

All works fine: I can upload programs and view output on serial monitor.

Everything is powered from the USB connection to the FTDI. I'd like to use an 1A extra VCC to power everything for stability.

How should I hook up VCC and GND?
I tried using VCC and ground from the 1A VCC and just connect TXD and RXD from the FTDI (FTDI gets is VCC and GND from USB).

I tried this:

FTDI RXD ---> Arduino TXD
TXD ---->Arduino RXD

1A VCC ---> Arduino VCC
1A GND----> Arduino GND

Serial monitorin works but uploading new programs does not. What am I missing here?

Unfortunately uploading programs failed, allthough serial

You also need to have the ground and DTR pins of the FTDI connected to your Arduino.

FTDI DTR ---> Arduino RESET
FTDI GND ---> Arduino GND

If I have

FTDI DTR —> Arduino DTR
FTDI RxD —> Arduino TxD
FTDI TxD —> Arduino RxD
FTDI VCC —> Arduino VCC

1A GND —> Arduino GND

Everything works

But with this setting IDE won’t upload and shows an error message:

FTDI DTR —> Arduino DTR
FTDI RxD —> Arduino TxD
FTDI TxD —> Arduino RxD

1A VCC —> Arduino VCC
1A GND —> Arduino GND

It get an error message from IDE: “avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0xe0” etc.

As I said before, you need to connect the FTDI ground to the Arduino in addition to having the 1A power supply's ground connected to it. Without a ground connection, there is no circuit between the Arduino and the FTDI.

Thank. That solved it.

You're welcome. I'm glad to hear it's working now. Enjoy!