Waveshare HAT User Manual page 8

Stepper Motor HAT User Manual
The DRV8825 is e has two H-bridge and a microstepping indexer, and is intended
to drive a bipolar stepper motor. It supports up to 1/32 microstepping. Internal
shutdown functions are provided for overcurrent, short circuit, under voltage lockout
and over temperature.
VM：Voltage input, range: 8.2V~45V, consider of regular, the actual input range is:
8.2V~28V
nSLEEP: Should keep High, otherwise chip will enter sleep mode, and module cannot
work properly.
nENBL: Enable pin. Low: H-bridge is enabled and rise edge of STEP is sampled; High:
H-bridge is disabled, output is high impedance. Note that you should disable it if
you don't use it, otherwise the chip and motor will keep heating!
STEP: Step clock input
DIR: Direction control
MODE0, MODE1, MODE2: Mcirostepping input
PIN 12/PIN 13: Adjust output current
R13/R16: Sample resistors, they are 0.2Ω
According to datasheet Page11:
Ichop = V(xREF)/(5*R(ISENSE))
and resistor is 0.2Ω, then we can get that output current is proportional to voltage of
potentiometer.
I = Vref
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