I have found some information on the net and I connected both items the following way:
5V => VCC5
GND => GND
TXD => RX1
RXD => TX0
DTR, 3V3, RTS and the last GND were left unconnected.
I tried to upload to the Arduino-Atmel board of the RTFpixel Led Ring, but get the following error:
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x00
Anyone has an idea what's going on or a link where I could find a tutorial how to program those led rings?
Thanks in advance for your help...