Input pin current ATmaga324P

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Hi !

 

I'm just checking if I got this alright.

 

Datasheet http://www.atmel.com/Images/Atmel-8011-8-bit-AVR-Microcontroller-ATmega164P-324P-644P_datasheet.pdf 

 

p. 325  says :

 

DC Current per I/O Pin ............................................... 40.0 mA

 

 

I'd like to drive few LEDs with 7mA to GND  through pins.

 

 

The reason why I'm asking this is because I've damaged few pins on ATmega128RFA1 by doing this.

On this chip there are actually registers (DPDS0 and  DPDS1) which tell how many mAmps can flow through pins.

 

 

So if I drive LED with 7-8 mA on ATmega324P won't be a problem?

 

Thank you !

 

 

 

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Won't be a problem if you remember to use a series resistor for each led.

 

Ross McKenzie ValuSoft Melbourne Australia

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valusoft wrote:

Won't be a problem if you remember to use a series resistor for each led.

 

Yes of course, I forgot to mention series resistor.

 

Thank you !

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drive LED with 7-8 mA on ATmega324P

Unless you need to see daylight with the LED's light some quality LEDs will be happy with half that.

John Samperi

Ampertronics Pty. Ltd.

www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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xtal_88 wrote:

p. 325  says :

 

DC Current per I/O Pin ............................................... 40.0 mA

 

The line you quote from the datasheet is for "Absolute Maximum Ratings".

Anything above that may damage the part.

 

Further down the page you will find:

VOL Output Low Voltage(3) | IOL = 20 mA, VCC = 5V | 0.9 volts
                                            | IOL = 10 mA, VCC = 3V | 0.6 volts

3. Although each I/O port can sink more than the test conditions
   (20 mA at VCC = 5V, 10 mA at VCC = 3V) under steady state
   conditions (non-transient), the following must be observed:
   1.)The sum of all IOL, for ports PB0-PB7, XTAL2, PD0-PD7 should not exceed 100 mA.
   2.)The sum of all IOL, for ports PA0-PA3, PC0-PC7 should not exceed 100 mA.
   If IOL exceeds the test condition, VOL may exceed the related specification.
   Pins are not guaranteed to sink current greater than the listed test condition.

 

Last Edited: Mon. Dec 1, 2014 - 09:10 AM
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You can use "low current" LEDs that only need 2mA's for full briteness!

 

JC
 

 

(Possum Lodge oath) Quando omni flunkus, moritati.

"I thought growing old would take longer"