Want to use other FTDI chip


I am going to develop arduino mega 2560 with less space so I have decided to develop my own board. Now I have a problem that for programming the controller using USB cable, Arduino have ATmega16U2 chip for USB to UART convesion. This chip is not available in India. So I decided to use FT232 chip. So can I use the same boot loader program that is available on Arduino site? I mean if I will use FT232 FTDI chip instead of ATmega16U2, then do I have to need to make any changes in boot loader program? Will it work for FT232?

Please help me to solve this problem.

Thanks. Chirag


I use a Sparkfun USB to serial converter and it works perfectly this has the FT232RL chip, see... https://www.sparkfun.com/datasheets/DevTools/Arduino/FTDI%20Basic-v21-5V.pdf

The ATmega16U2 would have to have the code for the USB to serial conversion loaded into it using the ICSP port so it would be a "chicken and egg situation for you. I understand the only reason Arduino went to the 16u2 chip was for cost reasons and their relationship with Atmel.

The FTDI chip is a lot less fuss as it just slots in without the need for programming.


Ya, you’re fine with the FTDI chip. It’s frankly got a few advantages over the 16u2.

A CH340G can also be used.

All it’s doing is usb <-> serial.

Ftdi used to replace atmega16u2 in older versions, so basically yeah it will work without changes.

Last question to Andy,

For the connection point of view, I just want to confirm that the serial connections of the FTDI chip would directly be connected to the UART pins of the ATmega2560 right?

Can you please direct me for the connection of FT232 to ATmega2560?

I will be thankful to you.

Thanks. Chirag

Yes, FT232 can be directly connected to ATmega's UART but it is good to connect both Tx and Rx via serial ~1k ohm resistor.

EDIT: In case of vagueness look at this schematic http://arduino.cc/en/uploads/Main/arduino_NG_schematic.png. I think, it is exactly what you're looking for.

As long as you make the right connections, which USB to TTL adapter you use makes no difference at all to either the IDE or bootloader.

What you do need (for Windoze) is the corresponding driver.