atmega328 custom board FT232RL issues

Hi there,

Until now I used arduino nano on a self-designed board (with a socket for it) to drive some 7 segments leds via SPI, one OLED via I2C. Everything great, works perferctly.

Weeks ago I dediced to not use the nano anymore but to use an ATMEGA328 DIP directly.
I followed all the istructions, burned the bootloader, tested the megas (swapping with the original on the UNO R3 board). I attach the schematics

Since I need the USB interface, I opted for the FT232RL (that unfortunatly is SSOP format)

Today I soldered the components, I had very bad troubles with the FT232RL, but at the third try I succeded to solder it without any apparent bug. I have no problems with SOIC, but SSOP is another thing.

I then attached the usb cable to the pc and powered on, and voilà the device appeard on linux as TTYUSB0. So I unplugged, pushed in an ATMEGA on the socket and tried to program it via the IDE
It started giving errors.
Unplugged, plugged in another time and now it doesn’t show up anymore as USB device, but I get errors like these: (rebooted the pc too)

296.801920] usb 2-1.1: new low-speed USB device number 49 using ehci-pci
[ 297.217926] usb 2-1.1: device not accepting address 49, error -32
[ 297.218081] usb 2-1-port1: unable to enumerate USB device
[ 314.166462] usb 2-1-port1: Cannot enable. Maybe the USB cable is bad?
[ 314.246253] usb 2-1.1: new low-speed USB device number 52 using ehci-pci
[ 314.326253] usb 2-1.1: device descriptor read/64, error -32
[ 321.190591] usb 2-1-port1: Cannot enable. Maybe the USB cable is bad?
[ 321.686379] usb 2-1.1: new low-speed USB device number 55 using ehci-pci

rarely I get:
[ 907.312127] usb 2-1.1: new full-speed USB device number 73 using ehci-pci
[ 907.427506] usb 2-1.1: New USB device found, idVendor=0403, idProduct=6001
[ 907.427513] usb 2-1.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 907.427517] usb 2-1.1: Product: FT232R USB UART
[ 907.427521] usb 2-1.1: Manufacturer: FTDI
[ 907.427525] usb 2-1.1: SerialNumber: xxxxxxx
[ 907.472262] usbcore: registered new interface driver usbserial
[ 907.472286] usbcore: registered new interface driver usbserial_generic
[ 907.472305] usbserial: USB Serial support registered for generic
[ 907.478075] usbcore: registered new interface driver ftdi_sio
[ 907.478099] usbserial: USB Serial support registered for FTDI USB Serial Device
[ 907.478235] ftdi_sio 2-1.1:1.0: FTDI USB Serial Device converter detected
[ 907.478289] usb 2-1.1: Detected FT232RL
[ 907.478633] usb 2-1.1: FTDI USB Serial Device converter now attached to ttyUSB0

Two things:

  1. is the circuit wrong on the usb side ? (I followed the duemilanove schematics)
  2. The cable: I use only D+, D-, GND. I don’t use V+ because the board is powered by a battery. This setup worked great with the arduino nano board

So I have: [Board]-3PINS(D+,D-,GND)-first cable female 20cm-standard usb cable 1m-PC

Can someone help with this ?
I attach the schematics.
Thank you

i just uploaded a sketch successfully on the board.. 10 seconds after completion I got usb disconnection:

[ 4011.920449] ftdi_sio ttyUSB0: usb_serial_generic_read_bulk_callback - urb stopped: -32 [ 4011.920791] ftdi_sio ttyUSB0: usb_serial_generic_read_bulk_callback - urb stopped: -32 [ 4011.921308] ftdi_sio ttyUSB0: failed to get modem status: -32 [ 4011.922847] ftdi_sio ttyUSB0: failed to get modem status: -32 [ 4011.924223] ftdi_sio ttyUSB0: failed to get modem status: -32 [ 4012.115963] usb 2-1.3: USB disconnect, device number 115 [ 4012.116107] ftdi_sio ttyUSB0: error from flowcontrol urb [ 4012.116334] ftdi_sio ttyUSB0: FTDI USB Serial Device converter now disconnected from ttyUSB0

Maybe the copper shield on the cable that I cut is giving RF issues ?

Your FTDI reset pin is floating. As far as I know it should be pulled to 5V with a capacitor to GND. Without a connection it might incidentally reset your USB connection.

The soldering is very questionable, pins 24 through 27 do not appear connected. The FTDI232 should be removed, board cleaned and leveled with desoldering braid and a new part installed properly. Google YouTube for “smd drag soldering”, it’s easy with common tools.