Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronic 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

Schmitt input for xilinx's spartan2 design.

Status
Not open for further replies.

zcq

Advanced Member level 4
Joined
Jul 14, 2001
Messages
102
Helped
1
Reputation
2
Reaction score
0
Trophy points
1,296
Activity points
619
Anybody know is it possible to set the schmitt input for spartan2 fpga?
I can not find it in the databook. If not,why?

Thanks a lot!
 

zcq

Advanced Member level 4
Joined
Jul 14, 2001
Messages
102
Helped
1
Reputation
2
Reaction score
0
Trophy points
1,296
Activity points
619
Any comment is welcome. Thanks!
 

Maddin

Member level 5
Joined
Sep 26, 2001
Messages
94
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Location
Europe
Activity points
842
zcq,
what do you mean with schmitt inputs? schmitt-triggered inputs that might be used to debounce your input signal(s)?? If you need to debounce your signal, try to use shiftregisters that "detect" your edges and logical state of the signal (as far I remember there is some additional register available too in near of the pad, but I'm not sure)
Hope it helped,
Maddin
 

zcq

Advanced Member level 4
Joined
Jul 14, 2001
Messages
102
Helped
1
Reputation
2
Reaction score
0
Trophy points
1,296
Activity points
619
Yes, i want to set the input signal pad as schmitt-triggered to act as a debouncer. Is it possible?
 

Maddin

Member level 5
Joined
Sep 26, 2001
Messages
94
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Location
Europe
Activity points
842
zcq said:
Yes, i want to set the input signal pad as schmitt-triggered to act as a debouncer. Is it possible?
I haven't used this feature yet, but I think it should be possible by editing the ucf (user constraint file) or passing some attribute in your HDL code ;
please check the docu or maybe somebody else can help you, sorry for any inconvenience.
Maddin
 

snake

Member level 4
Joined
Jan 22, 2003
Messages
79
Helped
3
Reputation
6
Reaction score
0
Trophy points
1,286
Activity points
639
I m not sure but i think that in constrains you can make it work, there you have some options like registered inputs or outputs i dont remember exatly.

by people.
 

bubber1974

Newbie level 3
Joined
Dec 23, 2002
Messages
3
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
26
Is it at all possible to configure Spartan II-IOBs as schmitt triggers? I don't think so!
 

happytronic

Newbie level 4
Joined
May 14, 2003
Messages
7
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
63
I think the inputs are by definition kind of shmit triggers, as you can set input levels to TTL or CMOS. a '1' is detected for a certain analogue level, which isn't the same as a '0'.
But if you want to debounce a signal digitaly for a switch, a shmit trigger is not what you need, as the input signal will go from high to low several times. a simple way to do it is is use register with a slow clock


process(clk)
if clk'event and clk='1' then
registered_1<=input;
registered_2<=registered_1;
output<=registered_1 and registered_2 and input
end if;
end process;
 

Status
Not open for further replies.
Toggle Sidebar

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top