To hook up the ssc-32U to the PI, you will need a SparkFun Voltage Level Translator or something similar.
The ssc has a logic level of 5 volts, the PI level is 3.3v.
So you would hook the low side power/ground to the PI. For the ssc side, I only needed to hook up the ground.
TX on the PI goes to RX on the ssc, RX on the PI goes to TX on the ssc.
Be sure that when you attached your servos to the 3d printed parts, they were centered. I use "Lynx SSC-32 Terminal" to center the servos and adjust them after everything is assembled. The femur should be horizontal, the tibia should be vertical when mounting.
I mounted my ssc with the power connections facing the rear of the hexapod. If you mount your ssc similarly, you can attach the servos as follows.
You should have the hexapod frame with mounted servos in front of you with the ssc power connectors facing you.
Starting with the left rear leg and proceeding clockwise, the servos are plugged into the ssc as follows:
Coxa - 20
Femur - 19
Tibia - 18
Coxa - 24
Femur - 23
Tibia - 22
Coxa - 28
Femur - 27
Tibia - 26
Coxa - 12
Femur - 11
Tibia - 10
Coxa - 8
Femur - 7
Tibia - 6
Coxa - 4
Femur - 3
Tibia - 2
After you have everything plugged in, you should use the "Lynx SSC-32 Terminal" to set all the servos to the 1500 position or center with the "All=1500" button.
Then click the "All=0" button.
To adjust the joints that are not centered, click the "Reg." button. A window will open, at which point you will need to click the "Read" button.
Then check the Global check box, and the "Initial pulse offset" check box. Then click write.
For the joints that are not aligned, click the radio button on the left next to the number that corrosponds to the servo.
When you do that, you will be able to use the "Offset" scrollbar to adjust the center position of that servo. What I found works best, is to do a joint then clicking - write -> Exit -> "All=0" before adjusting the next servo.
It is a little tedious but the closer things are lined up, the better the results.