Using L297-L298 integrated circuits manufactured by SGS Thomson (ST) can be made a control circuit for a stepper motor with two phase bipolar or unipolar four-phase (maximum current allowed on stage is 2 A).
This integrated motor driver generates control signals for the double stator and allows selection of travel direction and execution of a full step or half step, through proper planning its inputs, TTL compatible.Control of current good results because it allows the stepper motors to be connected to a voltage higher than that allowed for the command voltage.
An internal oscillator sets a flip-flop at the beginning of each period, when the stator windings are connected to power supply.
Synchronization of L297 oscillators is required when, in one system are used more circuits and motor control. It is easily achieved by mounting one control panel components P2, R11 and C1, and applying the output SYNC signal available at SYNC pin to other boards.
Another component of the assembly, IC3 divider, is designed to provide the clock signal when the output of the computer could be programmed to branch to step frequency required. Order cycle for a given signal SYNC divider taken from L297, and the block of jumpers K1 allows selecting one of the 7 available clock frequency (frequency step).
5 and 40 V power supply should not be stabilized but is required filtering. Maximum frequency of the steps increases with voltage, but not exceeded its limit of 40 V.
The current is adjusted with P1.