Toggle a GND-switch

Projects General Guidance
1

Hi,
I bought a L297/L198 stepper-motor-controllerboard (SMCB) wich originally wasn´t designed for the arduino. I thought that this shouldn`t be a problem, but now its getting complicated.
As the control-connection the board has 10 Pins: A 5V logic voltage, a GND and 8 for the control.
All the control-pins have all already Pull-up resistors and are switched by connecting to GND. I tried a bit, but I am not completely satisfied.
Please help.

1.) I could not simply connect a SMCB-Pin to a Arduino-Pin in INPUT-Mode. This won`t work. Should it?
2.) By manually connecting the SMCB-Pin to the Arduino-GND it would switch as wanted.
3.) I connected the SMCB-Pin to the GND via a relais. Switching the relais via an Arduino-OUTPUT-Pin works.
4.) I now could build kind of a "translation-board" with 8 relais and connections for Arduino and the SMCB, but isn´t there an easier way to do it?

Hope you can help.

Regards,
Kevin

2

Can you post a link to a spec of the device?

I could not simply connect a SMCB-Pin to a Arduino-Pin in INPUT-Mode. This won`t work. Should it?

What is in "INPUT-mode"? The Arduino?

3

Hi,
The documentation of the device is written in german. If there are any questions I might help.

pinMode(intPinStep, INPUT);

Thanks,
Kevin

4

You'd want controls to a motor shield to outputs, wouldn't you?

5

The strange thing is, that the motor board switches its state if its Pin is connected to a GND, not to 5V.

6

The strange thing is, that the motor board switches its state if its Pin is connected to a GND, not to 5V.

If the pin is pulled up, that is what you would expect to happen.

7

Sorry. You are completely right.
But than I have to search for a other reason why it doesn`t work and why the relais-solution works fine.

8

Have you still got the control pins set as inputs?
They should be outputs.

9

No,
I have set them to output and I can measure a change in current when switching from HIGH (0.002V) to LOW (4.8V). To GND it is 4.8V as well, but with GND it would switch, and with LOW-Pin it would not... Am I getting crazy?

10

I have set them to output and I can measure a change in current when switching from HIGH (0.002V) to LOW (4.8V).

That doesn't make sense.
Can you post code?

11

I do not really have a code yet.
If I connect the SMCB-Pin1 to the Arduino-GND the motor would do a step.
If I connect the same Pin to either Arduino Pin 4, 5 or 6 the motor would not do a step although I measure the same current.

int intPinEnable = 4;
int intPinDrehrichtung = 5;
int intPinTakt = 6;

void setup() {
  Serial.begin(9600);           // set up Serial library at 9600 bps
  Serial.println("Stepper test!");

  pinMode(intPinEnable, OUTPUT);
  pinMode(intPinDrehrichtung, OUTPUT);
  pinMode(intPinTakt, OUTPUT);
}

void loop() {
  Serial.print("\nloop\n");
  
  digitalWrite(intPinEnable, HIGH);
  digitalWrite(intPinDrehrichtung, LOW); 
  
  Serial.write("LOW");
  digitalWrite(intPinTakt, LOW);
  delay(40000);
  Serial.write("HIGH");
  digitalWrite(intPinTakt, HIGH);
  delay(4000);
  
  Serial.print("\nENDE");
  delay(500);
  Serial.print("\n");
  while(1);
}
12

I just realized, that the motor would not move, if I connect SMCB-Pin1 to the Arduino-GND through the multimeter (while measuring current).
And I do not measure any electric current (or < 1µA).
Is this a hint for anyone? Anyone any idea?

correction: I misused the word "current". Please check the units to get what I meant - sorry.

13

There shouldn't be any problem driving the board directly from Arduino pins configured as outputs - no need to worry about that at all.

14

I thought it should be no problem, but it is!
I am not worried, but frustrated.
It doesn´t work and I have no clue why...

15

And I do not measure any electric current (or < 1µA).

Some multimeters have different sets of terminals for measuring current - did you rememeber to swap?

16

The multimeter I am using is autorange and I have set it to µA/ DC - if this is what you where asking for.

But I wasn`t sure if there has to be a current?!?

17

Might it be, that either my Arduino or the motor-board has some kind of malfunction or is there any other explanation for this behavior? Does anyone have any idea what I might check or what I might do wrong?