I have an Arduino Mini Pro and a CP2102 USB to TTL module as in the image below:
I couldn't find a suitable guide for the module I have. So, how should I wire them together?
Vcc -> Vcc (Make sure your arduino accepts 5V supply) GND -> GND TXD -> RXD RXD -> TXD
Not much else to it, really.
There's a video explaining how to wire them up right here: http://www.youtube.com/watch?v=Vawhrr4COjI
Having tried many of the ideas here and elsewhere to resolve the "stk500_getsync(): not in sync: resp=0x00" error eg. swapping Tx with Rx, holding the mini pro reset button until uploading of compiled sketch, etc. The thing that worked for me was to turn on verbose output and press the onboard reset button when the (orange) uploading text was shown - works every time for me.
To make it work , one easy approach is to disconnect the RST header pin from CP2102 pin 9 and connect it to the RST pin (pin 24) instead. While in the Arduino schematics, the reset pin is connected to the ATmega328P pin 1 (RST) via a 100 ohm resistor, this connection is not strictly needed as pulses from the DTR pin (connected to ATmega328P pin 1 via a 100nF capacitor) will reset the MCU properly during programming.
I have just bought myself a Arduino Pro Mini for a project and struggled with the wiring for the FDTI connection. This is what worked for me:
GND -> GND - -> CTS VCC -> 5V RX1 -> TDX TX0 -> RXD DTR -> DRT
My Arduino also had a second GND pin on the header, which I didn't wire anywhere.
Hope this helps others with the same conenction issues.