CP2102 upload to mini pro without DTR pin?

I buy a USB to TTL with CP2102 chip, there are 6 pins as the attachment picture–

3.3v
RST
5V
TXD
RXD
GND

I want to use it for arduino mini pro, but I have no idea how to connect it. I research some topic here, someone said that it needs a DTR pin, there is no DTR pin on my CP2102 board. Anyone can help me? thanks!

You need another usb-serial-ttl board. One with DTR.
The CP2102 uses 3.3V signals. A DTR of 3.3V might not be enough to reset a 5V Arduino.

I have one with all kind of signals on the sides, like this one:
www.ebay.com/itm/NEW-CP2102-USB-2-0-to-UART-TTL-6PIN-Module-Serial-Converter-/170813830162

I have just received two identical or similar boards. You sure can use them to program an Arduino Pro. Connect it as usually:
Arduino / Converter
GND <-> GND
RX <-> RX
TX <-> TX
VCC <-> 5V or 3.3V depending on your Arduino Pro Version (or don’t connect if you have separate power for your circuit)

When programming from Arduino IDE, press and hold the Reset button during compilation and release it after information about sketch size appears and state changes to “Uploading”. Uploading should begin and succeed.

In case of problems - connect RX to TX and TX to RX (this is the usual pin labelling scheme with other converters).

If you want automatic reset and upload - some precise soldering and trace-cutting is needed. Google it if interested.

That particular CP2102 module is tough to modify.
You can cut the trace to the RST pin and add a wire from the header pin to pin 28 of the chip (DTR OUT).

Other modules have DTR out to a hole where a header pin can be installed.
DTR pulls a cap low to reset the uC, and the reset pullup resistor brings it back to 5V, so it doesn'tmatter if DTR only goes back to 3.3V on the CP2102 side.

mszkutnik:
I have just received two identical or similar boards. You sure can use them to program an Arduino Pro. Connect it as usually:
Arduino / Converter
GND <-> GND
RX <-> RX
TX <-> TX
VCC <-> 5V or 3.3V depending on your Arduino Pro Version (or don’t connect if you have separate power for your circuit)

When programming from Arduino IDE, press and hold the Reset button during compilation and release it after information about sketch size appears and state changes to “Uploading”. Uploading should begin and succeed.

In case of problems - connect RX to TX and TX to RX (this is the usual pin labelling scheme with other converters).

If you want automatic reset and upload - some precise soldering and trace-cutting is needed. Google it if interested.

Hi mszkutnik, I’ve this kind of CP2102 also (see attached image) and your suggestion is not working on me. What I might have missed?

SOLVED!!! After several attempts, I got it working. Thanks mszkutnik.

What was the fix?

Make sure three things in Arduino IDE:

  1. Correct "Board", mine: "Arduino Pro or Pro Mini (5V, 16 MHz) w/ ATMega 328"
  2. Correct "Serial Port"
  3. Correct "Programmer", I pick: "AVR ISP"

Then apply mszkutnik steps above.

You really don't need DTR pin, RST pin or auto reset thing.

mszkutnik:
I have just received two identical or similar boards. You sure can use them to program an Arduino Pro. Connect it as usually:
Arduino / Converter
GND <-> GND
RX <-> RX
TX <-> TX
VCC <-> 5V or 3.3V depending on your Arduino Pro Version (or don’t connect if you have separate power for your circuit)

When programming from Arduino IDE, press and hold the Reset button during compilation and release it after information about sketch size appears and state changes to “Uploading”. Uploading should begin and succeed.

In case of problems - connect RX to TX and TX to RX (this is the usual pin labelling scheme with other converters).

If you want automatic reset and upload - some precise soldering and trace-cutting is needed. Google it if interested.

works for me. haha.

press and hold the Reset button during compilation and release it after information about sketch size appears and state changes to “Uploading”.

It works as you manually reset the Arduino. I have had/build older Arduino compatible boards that did not reset automatically (using DTR). I had to hold the reset button to upload the program/sketch.

(Sorry for reviving an old thread, but I was looking for information about topic and I have something to add for people who might search the forum in future)

I have the "D-SUN USB to TTL" dongle, red pcb and wrapped in transparent plastic, with 5 pins: +5V GND RXD TXD 3V3.

Connect RX->TX and TX->RX (and of course GND and appropriate VCC).
It worked for me only when I chose "Programmer: AVRISP MkII" (and press reset on the pro mini while compiling as said before).

Arduino IDE 1.6.10, Mac OsX El Capitan

Bye,
Matteo

5V—-VCC

Gnd—-Gnd

Tx—-Rx

Rx—-Tx

Thats it

Once you click on the upload button, the code will be compiled and at that time the status bar on the bottom will be changed to “Compiling”. At that time, press and hold the reset button the Arduino Pro Mini

Once the code is compiled, the status will be changed to uploading. Now release the reset button and the code will be uploaded in no time.

You will find more info there

Hello help needed to upload my pro mini board via CP2102 USB to TTL serial converter. I have tried all the suggestion in this topic to no avail. I tried measure the 5 V, there is no voltage at the pro mini and the serial board connected. There is a 5V when unplug to the pro mini board. pro mini board is a 5V 328ATMEGA 16mHz.
Am I using the wrong serial board? it is a 5 wires type. I have tried swapping TX & RX vice versa, problem indicated as problem uploading the board and programmer not working. Appreciate someone could help out. Thanks.

For me the RST Pin on the USB to TTL worked when I connect it to the DTR-Pin on the Board

Maybe you have selected the board "Arduino Mini", but you must select the board "Arduino Pro or Pro Mini".

At least this is what just happend to me :slight_smile: and what made it work after all.

Also select the programmer "USBasp".

Thanks to Arduino PRO MINI – How to upload code | alselectro