FTDI to standalone ATMEGA 328 sync issue

Other Hardware 3rd Party Boards
1

Trying to program an atmega328 project and experiencing some issues with my FTDI to usb adapter.
The adapter is an ft232RL chip from inland, bought here: http://www.microcenter.com/product/432350/FTDI_Adapter_USB_Controller.
Schematic:

The interesting thing about my problem is that I can program the project fine using an arduino as an ftdi adapter. I connect the RX,TX, 5V, GND, and DTR pins on the uno to the corresponding pins on the project, and the sketch uploads successfully.

It's only when I do the exact same thing with the adapter that I reach problems, the avrdude: stk500_getsync()

Drivers are installed, the computer sees the device.
It's the only USB plugged into the computer (COM3) and is selected in the IDE.
Board selected is the Arduino UNO.
DTR is connected to the adapter via a .1 uf cap.

Again, I can program with a normal arduino as an ftdi adapter just fine, so I'm really confused. Thanks again for any help.

2

I know the adapter itself works as well. I tested it on a pro mini, and it works fine there. so obviously a board issue.

3

Does the board reset automatically when you press upload? (Connect an LED + resistor to D13 (PB5, physical pin 19) and see if it blinks when you reset.)
Did you connect TX of the adapter to RXD of the ATmega, and TXD of the ATmega to RX of the adapter?

You might want to add a diode to the reset pin to prevent the ATmega from going into HV programming mode. (Take a look at these schematics + simulations for the auto-reset circuit, it's for the ESP8266, but the principle is the same.)

Pieter

4

I tested the light- The board does auto-reset, but i still get the sync issue. I tried switching the RXD and TXD on the adapter to the board- no luck. My reset circuit is identical to that of the pro mini and arduino-to-breadboard tutorial. Thank you @PieterP

5

I added the diode too. No difference.

6

Should rx be connected to tx?

7

When using the Arduino as USB-to-Serial converter, you connect TXD of the ATmega to the "TX" pin of the Arduino, and the ATmega's RXD to the "RX" pin of the Arduino. This is because on the Arduino, "TX" is connected to the RXD pin of the on-board USB-to-Serial converter (ATmega16U2), and "RX" is connected to TXD of the USB-to-Serial converter.

When using an FTDI converter, you need to do the same thing: the ATmega's TXD to the FTDI's RX(D) and the ATmega's RXD to the FTDI's TX(D).

Pieter