Stepper Motor Controller Board

The heart of the stepper controller board is the L297 Stepper Motor Controller IC (U1) and the L298 Dual H-Bridge IC (U2). Both chips are provided by ST Microelectronics. Data sheets are available at L297 and  L298

Logic-level inputs, sync oscillator signal, common voltage (VCC) and common ground (GND) are taken from J2, an 8-pin connector. The pin connections are as follows:

  • Pin 1: GND
  • Pin 2: Sync Oscillator Signal
  • Pin 3: N.C. reserved for future use - tied to GND for now
  • Pin 4: Half/Full Step Select - logic high selects half-step, logic low selects full step
  • Pin 5: Step Clock - logic low pulses advance to the next step
  • Pin 6: Clockwise/Counter-Clockwise Select - logic high selects clockwise, logic low selects counter-clockwise
  • Pin 7: Enable - logic high enables the L297 chip
  • Pin 8: VCC (+5VDC)

A 4-wire stepper motor is attached to the board at J3, a 4-pin connector.

  • Pin 1: Phase A
  • Pin 2: Phase B
  • Pin 3: Phase C
  • Pin 4: Phase D

Power for the stepper motor (V+) is provided at J1:

  • Pin 1: Ground (GND)
  • Pin 2: V+ (up to +40VDC)