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Custom project board in progress...

Bydent

Hi, I have a spare PICAXE 28x1 and L293D that I want to use for my first custom built circuit. But i have no clue what to do!!! The diagrams on the Picaxe website are so confusing and the ones in the manuals only show the pinouts. Can I just hook up 4.5 volts? Or do I need fancy shmancy support circuitry like capacitors and stuff? 

Thanks guys! 

UPDATE:

I have a diagram of the L293D and it is nice to have, but very confusing.

Picture_2.png

I need somebody who is experienced enough at reading these things. See, my problem is what the pin labels mean. I have another diagram for that...

Picture_3.png

... but it is not very helpful either. 

My problem is:

Which wire do I connect to all of these? Battery negative to Vs??!! And what are the "enable"s for?

Thanks again! (yes i sound kinda crabby, but it is just cuz i am hurrying) :) 

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Chris the Carpenter's picture

Vs is the supply voltage.

Vss is the logic supply voltage.

(I read these off of the chart you included in this post)

dent's picture
Man, you make me feel like an idiot. I meant are they positive? negative? 
robologist's picture

Look at the chip pins and think about it for a minute. If there are a number of ground pins present, then the other voltage pins are probably positive. So you have both sides, the negative connected to ground, and the positive connected to Vs(s).Usually when a max voltage is shown in a datasheet, it will be positive. They put on the minus signs on if they mean negative.

tom_jones's picture

@roboblogist, the ground pins on the picaxe board are the positive pins. the various V pins are supplying the power to the components and are negative.
tom j

robologist's picture
Uhh, Tom, I think ya got it a little confused there. And you run the possibility of confusing others, who may not know any better, into frying their chips.  Pins marked with a V are always positive, ground is always the negative reference point.
tom_jones's picture

i see my mistake. i misread board for a moment, thanks for pointing that one out robologist.

Tom J 

RascalRobot's picture
capacitors and stuff are not fancy shmancy. Yes, they are required unless you want your electronics to behave irratically. As far as the "enable" signal, ( I can't believe I am writing this ) it "enables" the outputs. I found out the answer by reading the datasheet for the L298D.
rik's picture

I found (from experimenting) that the enable pins on L293D are always enabling their outputs unless you pull them low. That means: unless you connect them to ground through a 10 kOhm resistor.

A floating enable pin will leave the outputs enabled. That means: not connected to anything.

The intended use is to connect them to V+ when you want to enable the outputs. Again: don't connect directly to V+, but through a resistor. You probably want to connect them to a digital output pin on the MCU. That's fine too. no resistor then.

jklug80's picture
If you search here for L293D someone made a tutorial with colored lines showing what goes where between it and a picaxe.
dent's picture
My blog has been touched by the frits! Rejoice!