Datasheet

But my motor already has a capacitor on it and it still doesn't work.

These motors generate a lot of brush noise and usually need the full 3-capacitor treatment for adequate

suppression.

Why don't you just design capacitors into the shield?

They would not be effective there. The noise must be suppressed at the source or the motor leads will act like

antennae and broadcast it to the rest of the system!

Why won't my stepper motor go any faster?

Since the shield is controlled by i2c, the maximum step rate is limited by the i2c bus speed. The default bus speed

is 100KHz and can be increased to 400KHz by editing the library file in your Arduino installation folder. The file can

be found in

hardware/libraries/wire/utility/twi.h

Find the line with: "#define TWI_FREQ 100000L"

and change it to "#define TWI_FREQ 400000L"

Or, you can add the following code to your setup() function: (Note: this line must be inserted

after

the call to begin())

TWBR = ((F_CPU /400000l) - 16) / 2; // Change the i2c clock to 400KHz

What I2C addresses are used by this shield?

The shield is addressable from 0x60-0x80. 0x70 is an "all call" address that all boards will answer to.