EE or CompE 's: VHDL question

[jmcoreymv]

Is there any function built into VHDL to do sequence detection? I know how to manually generate a state diagram for a required sequence detection and then implement it, but for long sequences this would seem to be extremely tedious and error prone. Is there a built in function to check to see if a specific sequence has been placed on an input?

 

[FrustratedUser]

I am just getting into VHDL so I can give no answers.

I am learning the development system for Xilinx. It's fully graphical and pretty easy to do state machines.
What system are you using?

 

[RaynorWolfcastle]

nope, not that I know of. You have to manually make the state machine for it.

 

[jmcoreymv]

Xilinx as well. And for the record I think Xilinx is POS. It doesnt handle file names above 8 characters, and it randomly chooses to terminate because of memory errors. Also when using the Impact App to upload code to development boards, it will randomly stop working and make you reboot your entire system.

 

[FrustratedUser]

Originally posted by: jmcoreymv
Xilinx as well. And for the record I think Xilinx is POS. It doesnt handle file names above 8 characters, and it randomly chooses to terminate because of memory errors. Also when using the Impact App to upload code to development boards, it will randomly stop working and make you reboot your entire system.

:Q

Yeah, the 8+3 filename $ucks. Other than that it looks fine, but this is my first venture into VHDL.

 

[mAdD INDIAN]

Originally posted by: jmcoreymv
Xilinx as well. And for the record I think Xilinx is POS. It doesnt handle file names above 8 characters, and it randomly chooses to terminate because of memory errors. Also when using the Impact App to upload code to development boards, it will randomly stop working and make you reboot your entire system.

Have you guys used Altera Quartus CAD system? That's the development suite we use in our University. It's pretty good and has some neat features related to doing schematic diagrams, but its kinda buggy at times.

 

[Maverick]

you guys doing this for school or fun? I'd love to learn some of this stuff on my own if its possible to do it at home without an engineering lab.

 

[jmcoreymv]

Nope, just use Xilinx, mainly just VHDL work now. Only used the schematic stuff at the very beginning.

 

[jmcoreymv]

Originally posted by: Maverick
you guys doing this for school or fun? I'd love to learn some of this stuff on my own if its possible to do it at home without an engineering lab.

You can download the ISE webpack software for free, and you can buy a development board at www.digilentinc.com for ~50 bucks. I think this is the one I used last quarter. Here

The one were using this quarter is quite a bit more powerful (Spartan 2, 200K gate) Here but its about 100 bucks.

 

[RaynorWolfcastle]

Originally posted by: Maverick
you guys doing this for school or fun? I'd love to learn some of this stuff on my own if its possible to do it at home without an engineering lab.

EE's and CE's do it for school, you might need a boolean logic and digital systems primer if you haven't read anything about it that. After that, all you have to do is go to altera's website and download the free development environment (Quartus Web Edition). Of course, it's more fun if you have the board that you can program they run something like $150 a pop for the ones we used this semester (They include a FLEX10K CPLD and a MAX7000 chip).

You can design some pretty fun stuff with just that. You can even build a simple MIPS microprocessor!

 

[blahblah99]

There's no function natively to VHDL that'll check for a sequence... however you can implement a shift register of N-bits long to check for your N-bit sequence.

and if the output of the sequence checker is sensitive to glitches, then you will have to latch it using a clock.

 

[mAdD INDIAN]

Originally posted by: RaynorWolfcastle

Originally posted by: Maverick
you guys doing this for school or fun? I'd love to learn some of this stuff on my own if its possible to do it at home without an engineering lab.

EE's and CE's do it for school, you might need a boolean logic and digital systems primer if you haven't read anything about it that. After that, all you have to do is go to altera's website and download the free development environment (Quartus Web Edition). Of course, it's more fun if you have the board that you can program they run something like $150 a pop for the ones we used this semester (They include a FLEX10K CPLD and a MAX7000 chip).

You can design some pretty fun stuff with just that. You can even build a simple MIPS microprocessor!

you goto UofT? Cause we use the exact same stuff.

 

[jmcoreymv]

If theres no built in function...is there an addin library that does sequence detection?

 

[jmcoreymv]

Originally posted by: blahblah99
There's no function natively to VHDL that'll check for a sequence... however you can implement a shift register of N-bits long to check for your N-bit sequence.

and if the output of the sequence checker is sensitive to glitches, then you will have to latch it using a clock.

If theres no built in function, this does seem like a pretty good way to do it. Thanks.