Input current for phillips P89V51RD2bn Microcontroller

Hi Guys,
Im new to Microcontroller. Im having phillips P89V51RD2bn Microcontroller. I would like to practice the embedded code. Instead of using development board, i like to design circuit on breadboard. So i got P89V51RD2 interface with 7 segment LED display.

From the diagram i see input volt 5vdc. But what current(I) i have to give? i read the phillips P89V51RD2bn data sheet, still cant find correct input current :-?? I dont want to damage or burn my microcontroller :sad:. Could you guys pls suggest me the correct input current?

Thanks

Hi,

you must not "force" current into the VCC pins. Instead you supply it with voltage: 5V DC.

The controller sinks only that current that it needs.
So if you don´t apply more than 5V you can not damage the part.

How much the controller sinks depends on a lot of parameters:
* clock frequency
* used internal periferals
* connected external periferals
* power safe modes
* ...

With your circuit the LED probbly consumes more power thanthe controller.
...about 20 mA per activated segment.

I didn´t look into the datasheet, but for the controller itself you may calculate with less than 30mA.

All of your circuit then consumes less than 200mA. Any suppply that can handle 200mA should be OK.
To be on the safe side (for future) us a 500mA or a 1000mA supply.

Klaus

Greetings,
Do not worry, what you need is called Voltage regulated supply(5 volt).
Here is a Post link : https://www.edaboard.com/threads/221061/
Please read the whole thread as it might help you understand few more things. Comment #8 will give you correct circuit image.
You can also use 12v, 1A adaptor to supply voltage to lm7805 voltage regulator(read lm7805 datasheet).

and here is another link related to P89v51 circuit & programming : https://www.8051projects.info/threads/need-help-using-8051-with-rs232.2283/

Good Luck )

From the datasheet, it looks like the P89v51 was never designed to source much current on the I/O pins. It just say the IO pins are pulled high when used as input.

On page 60 of the attached datasheet, Only P1.5, P1.6 and P1.7 has a max current sinking of 20mA, The rest of port 1 are 15mA current sinking. So in your case, if you use common anode 7 segment LED and with the same resistors, the current would not exceed 10mA on each segment then it should OK.

Allen

you may use 500MA current for the same, because your project is so small