Brochage

Brochage Driver de moteur pas à pas DRV8825 (support StepStick / Pololu)

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Broches

• ENABLE (active low — pulled low on the carrier, so the outputs are LIVE when this pin is left unconnected)
• M0 (microstep select bit 0 — pulled low; M2/M1/M0 = 000 full, 001 half, 010 1/4, 011 1/8, 100 1/16, 101 1/32)
• M1 (microstep select bit 1 — pulled low)
• M2 (microstep select bit 2 — pulled low; this trio replaces the A4988's MS1/MS2/MS3 and adds 1/32 stepping, and the truth table is plain binary, not the A4988's)
• RESET (active low — must be HIGH for the driver to step; on the bare carrier it is not driven, which is why a driver that looks correctly wired does nothing. Standard fix: jumper it to SLEEP)
• SLEEP (active low — must also be HIGH to run; jumpering SLEEP to RESET is the usual way to satisfy both at once)
• STEP (one rising edge = one microstep — hold each level at least 1.9µs, so no faster than ~250kHz)
• DIR (direction — its level is sampled on each rising STEP edge)
• VMOT (motor supply 8.2–45V, where the A4988 stops at 35V — fit a 100µF electrolytic directly across VMOT/GND, the connection inrush spike is the usual way these die)
• GND (motor-supply ground, the return for VMOT and both coils — 1.5A per coil bare, 2.2A only with a heatsink and airflow)
• B2 (coil B, one end)
• B1 (coil B, other end — B2/B1 occupy exactly the positions the A4988 prints 2B/2A, same pads, different naming)
• A1 (coil A, one end — set the current limit BEFORE plugging a motor in: on the DRV8825 the limit is Vref × 2, measured on the trimpot screw, not the A4988's formula)
• A2 (coil A, other end — never split one motor winding across an A pin and a B pin; find the two coil pairs with a multimeter before wiring)
• FAULT (open-drain, active low, pulled low on over-current or thermal shutdown — THIS IS THE PIN THAT DIFFERS FROM THE A4988, which has its VDD logic supply in this position. The DRV8825 has no logic-supply pin at all: it runs its logic off VMOT through an internal 3.3V regulator. Check what a socket built for an A4988 drives here before plugging one in)
• GND (logic ground, the return for STEP/DIR/ENABLE and the microstep pins)

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