Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

port of microcontroller

Status
Not open for further replies.

deepum

Newbie level 4
Joined
Mar 25, 2014
Messages
7
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Activity points
39
what is the meaning of open drain?
 

Open drain simply means that the port or pin in question is not connected to VCC or VDD. Which means that for you to use the port, a pull up resistor is often required to make the port be functional or else there is an open circuit better the power supply and the internal drain of the port.
 

Open drain simply means that the port or pin in question is not connected to VCC or VDD. Which means that for you to use the port, a pull up resistor is often required to make the port be functional or else there is an open circuit better the power supply and the internal drain of the port.



can you please tell why the word open DRAIN is there?
 

Open means that there is an open circuit between the port and vdd.
Drain means that the microcontroller in question is fabricated based on the MOS technology. A MOS has drain, source and gate. It is assumed that the source is internally grounded and the gate connected directly to the internal output of the microcontroller and the drain left open/ not connected to the Vdd.
So if you connect a resistor between the port and Vdd , you have successfully connected the drain to the power source thereby creating a complete connection.
 
  • Like
Reactions: deepum

    deepum

    Points: 2
    Helpful Answer Positive Rating
It's similar to open-collector outputs. The output is not "driven" but rather it floats when high and goes toward ground when low.
 
  • Like
Reactions: deepum

    deepum

    Points: 2
    Helpful Answer Positive Rating
Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top