the pics are hard to decipher, but I can post them. There is essentially no point in schematics as the connections are default, straight forward.
The motor is connected to the output of the driver right, no problems there, I know because it turns fine under step and direction.
The alligator clips you see provide 12 volts to the vmot input of the driver. Ground connects to the same ground.
The uart pin of the driver is connected through a 1kohm resistor to the tx1 pin, and directly to the rx1 pin of the mega 2560.
There appears to be no serial communication. I don't know how to debug it... all the connections appear to be right. I tried switching the code and connections to port 2, it did nothing. If I had an oscilloscope I would check to determine if there was any data even coming out the serial port of the arduino.
I checked to try to determine if it was because of changes that needed to be made to the code because this is a tmc2208 chip, not tm2209. That does not appear to be why, although it's probably a good idea to change the code.
Possibly it has something to do with the pdn pin. The uart pin and the pdn pin are supposed to be the same pin, yet they are different here. I don't know.
What I would really like to do is just determine if I can even get the stepper motor to run silently or not, before I spend all this time getting arduino code to work. I may buy an ftdi adapter and try using the configurator app, but it might not work anyway.