Connecting ATMega2560 chip to FTDI chip to PC

Other Hardware 3rd Party Boards
1

Hi

I have an ATMega2560 16U-IH chip connected to an FT232RL FTDI chip which is then connected to my PC. From the PC, I am able to see the FTDI chip but unable to communicate with the ATMega2560 chip.

The wiring:

PC (USB) -> FTDI chip: - see attached image
+5v (red USB wire) to Pin 20 (VCC). Also a 0.1uf non-polarised capacitor to GND and 10uf polarised capacitor to GND
GND (black USB wire) to Pin 7, 18, 21, 25 & 26 (GND)
D+ (green USB wire) to Pin 15 (USBDP)
D- (white usb wire) to Pin 16 (USBDM)

FTDI chip to ATMega2560 chip - see attached image
Pin 1 (TXO) to Pin 2 (PE0)
Pin 5 (RXD) to Pin 3 (PE1)

ftdi wiring
ftdi wiring999×410 57.7 KB

The ATMega2560 is also powered from the USB +5v and GND (power is getting to the ATMega2560 chip).

Is there anything I am missing here that would stop this from working?

2

In what sense? Not able to upload? Or a loaded sketch can't communicate with the PC?

Did you design your own board? If so, schematic please.

Your topic has been moved to a more suitable location on the forum. Installation and Troubleshooting is not for problems with (nor for advise on) your project :wink: See About the IDE 1.x category.

3

Unable to upload (it has a sketch already on the board which is also unable to speak to the PC).

Thanks BS

4

TX - Rx & RX to TX

Looks like you have RX to RX and TX to TX

5

I have:
FTDI 1 (TX) to ATMega2560 PE0 (Pin 2 - RX)
FTDI 5 (RX) to ATMega2560 PE1 (Pin 3 - TX)

Thanks BS

6

To elaborate:
I have installed the FTDI driver and I can see it under Ports in Device Manager (Windows) and ttyUSB0 in Linux.
I am (trying to) communicating with the ATMega2560 chip via the FTDI via serial in a program I've written in C. I can successfully connect to and communicate with an Arduino Mega (uses the same ATMega2560 chip) using my program and a program uploaded to the Arduino.
The ATMega2560 chip I am trying to communicate with has this same program burned to it.

7

@nickgammon
I am using your bootloader sketch and I get multiple verification errors (see attached .pdf
bootloadererror.pdf (80.3 KB)
file).
I am using a 0.1uf ceramic capacitor between VCC/AVCC and GND very close to the chip.

Thanks BS