Arduino Diecimila Pin Power Problems

Development Tools IDE 1.x
1

Dear Users

I recently obtained an Arduino Diecimila with the goal to drive a stepper motor through a L392D driver. (HTTP 301 This page has been moved)

The driver needs at least a power supply of 4.5 to work and I want to give the voltage by setting an output permanent to High. To drive the stepper motor I have 4 output pins. I don't have an extensive knowledge about stepper motors and I just tried to set the output pins to high or low and see if something happens. When nothing happened I measured the voltage coming from the output pins compared to the ground. (with nothing in between)

I noticed that the Voltage output coming from the pins (which are on high) is only 2.5V. This is not enough to drive the driver and searching the web I couldnt find any explanation about why this is happening. I didnt PWM the outputs (as far as I know).

Is there anyone who can help me.
Thanks in advance

2

If I understand you correct - you are trying to use an Arduino output pin as the Vcc supply to the L293D chip?

Stop that. You're going to damage yor Arduino and the reason it is called Vcc is that it needs a powersupply. The output pin is only 40mA capable. In fact you cant use the Arduino +5V pin (which comes from the powersupply) cause that only copes with 500mA (which could be enough for your motors, but I doubt it)

So the reason you measure too low voltage is that the protection circuits are trying to stop burning the Atmel. Unless it is too late.

(NB: this is not an "installation problem" - ask further questions in the "Motors" section)