Negative current.

[iz3kxw]

Hi guys,

Does anybody know the maximum negative current of an input of a Picaxe 08M2 ?
I mean to connect for example a diode led anode to supply (5 Vdc), the cathode to a resistor and than to the input of my Picaxe and light up the led when the input pin is in low condition.
I know the maximum positive current is 20 mA but i can't found the value of the negative.
thank's a lot.

iz3kxw
Andrea

 

[srnet]

The maximum current the 08M2 can source or sink is 25ma per pin.

 

[iz3kxw]

Hi srnet,
thank you for the information.
Andrea.

 

[hippy]

I mean to connect for example a diode led anode to supply (5 Vdc), the cathode to a resistor and than to the input of my Picaxe and light up the led when the input pin is in low condition.

If the LED is actually connected to an "input pin", then the current will be sunk by whatever is driving the input, not the PICAXE itself.

 

[bluejets]

Hippy,
I think you will find he is trying to drive a led but his description is a-about.

 

[Paix]

Perhaps the diagram will help Iz3kxw with the nomenclature. I don't suppose that I would be able to explain it clearly in Italian. .

 

[iz3kxw]

Hi Paix, what i mean is the connection of the upper led, the one which go on when output is low (sinking current), as srnet said is in this case 25 mA max. Right ?
Ciao de iz3kxw.

 

[Dippy]

The most precise and up-to-date data can only be obtained from the Microchip Data Sheet.(And Errata sheets often )

In Manual 1 Page 8 Rev-Ed state "Each output can sink or source 20mA."
and
"Total maximum current per chip is 90mA."
For some PICs this is a conservative figure, but at least it a safe value.

Sink = your question.
Source = what you call "positive current" , but do be aware of correct terminology.

In reality, this does vary depending on the base PIC, but you can only base your design on the figures given by Rev-Ed.

 

[Paix]

As Dippy says.
73 de G0PAi - Ian @ IO83XL

 

[iz3kxw]

In Manual 1 Page 8 Rev-Ed state "Each output can sink or source 20mA."
and Total maximum current per chip is 90mA."

Hi Dippy,
i'm sorry, i did not read carefully the manual 1 at Page 8, is clearly written "Each output can sink or source 20mA".
I did not know that the term "sink" is what i call negative current, thanks to you i've learned new terminology.
73 de iz3kxw Andrea qth-JN55RQ

 

[Paix]

I did not know that the term "sink" is what i call negative current.
73 de iz3kxw Andrea qth-JN55RQ

I understood what you were getting at, which is why I posted the diagram to clarify matters for you.