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.

Register Log in

Question about electronic terms (SMII/SS-SMII, TX, RX)

Status
Not open for further replies.
H

HOSSEINGHODS

Newbie level 3
Joined
Sep 27, 2016
Messages
4
Helped
1
Reputation
2
Reaction score
1
Trophy points
3
Activity points
28
Hi
Following sentences are some parts of a datasheet, please take a look at them and tell the difference between the marked terms.

  • In SMII/SS-SMII, TXD1 is not used and should be tied either high or low.
  • In SMII/SS-SMII, RXD1is not used and they are driven low.
  • RMII mode;no switch controller is connected; and TX_EN[7:0] is pulled down.
  • 'Pd' stand for internal pull down (75K ohm)

Thanks in advance.
 

HOSSEINGHODS said:
Hi
Following sentences are some parts of a datasheet, please take a look at them and tell the difference between the marked terms.

  • In SMII/SS-SMII, TXD1 is not used and should be tied either high or low.
  • In SMII/SS-SMII, RXD1is not used and they are driven low.
  • RMII mode;no switch controller is connected; and TX_EN[7:0] is pulled down.
  • 'Pd' stand for internal pull down (75K ohm)

Thanks in advance.
Click to expand...

Tied high means connected to Vcc using some current limiting resistor.

Tied low/driven low/pulled down/internal pull down means connected to gnd again using current limiting resistor.
 

Thanks, some other questions;
  1. consider a pin which is internally pulled up (with an internal 75 K ohm resistor), is it necessary to pull this pin up externally? I have seen people doing this!
  2. what does keep logic low level mean?
 

1. I think adding an external pull up resistor will leads to a strong pull up for that particular pin.

2. "keep logic low" --> connecting the specific pin to logic '0' voltage or pulled down.
 
Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top