Saturday, 26 September 2009

Switching the lights on

I swapped back to "playing" with my believed-to-be working stepper motor driver board. Looking back, I found Nophead's comment about connecting the enable pin to 0V in order to get the indicating LEDs working. I established from the instructions that the enable pin was pin 5 on the IDC socket, but I didn't know which was pin 5.

After some internet hunting, I eventually managed to confirm the identification of the pins relative to the ribbon cable wires. I thought. I tried that, and got nothing. Hmmm. After some more hunting, I found that my reference website had been wrong - but they're in good company, as Asus apparently got it wrong in their manuals and on their own website! Luckily, this being a communication type connection rather than power, nothing drastic happened when I'd connected the wrong pin.

Using this website, I got the right diagram.
Wire 1 on the ribbon cable goes to pin 1 on the IDC, which is at the end of the row adjacent to the tab on the male connector, shown here as on the top left of the connector, and pin 5 is marked with a wire.

In order to test the stepper motor driver board's indicating LEDs, the pin on the board's connector corresponding to pin 5 on the ribbon cable is connected to ground.
Here is a photo' showing the connector pins 5 (enable) and 9 (ground) linked with a wire.

After arranging this, I plugged in and switched on power to the working board - sure enough the LEDs lit, but one green on one side and one red on the other. Is this correct? Anyone know which ones are supposed to light up?


  1. Yes one of each pair of LEDs should be on. I think it will be pretty random because the reset pin of the chip is tied high so it doesn't get explicitly initialised.

    If you connect a motor then you should be able to control the intensity of the LEDs with the current control.

  2. My motors aren't yet wired....