Resistor tolerance for shunt current measuring

Obviously precision and accuracy count, so do I assume a 0.1, 0.5 or 1% resistor being used here?

It depends upon the needs of your project!

Do you want to measure 0A-3A at +/-1%? +/-0.1%? etc. The resistor tolerance affects this number, but it is also affected by which TI shunt monitor part you select.

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The Basic Motor Driver: simple, inexpensive motor driver for 1 stepper motor or 2 DC motors