Programmable Devices
CPLDs, FPGAs, SoC FPGAs, Configuration, and Transceivers
21609 Discussions

Does Altera have any function like SRL16E of xilinx

Altera_Forum
Honored Contributor II
3,087 Views

just like the title. 

if not ,any suggestion on why altera didnt take this architecture? 

patent or any profit without SRL16E(saving source? i think no)
0 Kudos
6 Replies
Altera_Forum
Honored Contributor II
1,700 Views

The Stratix III chips have "MLAB" mode which converts whole LABs into small memories. It uses the LUT mask bits for storage similar to the SRL16. It does not have built in shift wiring. Many shift registers can be shoe horned into the MLAB with a little external registering / logic. The MLAB method is more efficient in silicon. Personally I'd rather pay a little more for my chips and have a vanilla shift register.

0 Kudos
Altera_Forum
Honored Contributor II
1,700 Views

Quartus will automatically convert wide/large shift registers into alt_shift_taps megafunctions. (This is the "shoe-horn" method that uses a small memory and an external counter to do the logic.) Functionally it's identical to a shift register. 

 

To be honest, I think the SRL16 looks better and would provide better area. Yet I've converted many design with them(especially DSP designs) and have yet to see one where they had an area advantage. I admittedly have always been surprised by this, but have seen it time and time again. I'm sure such designs exist but don't know about them and doubt if they're common. (What I am sure is common, are there are a lot of X designers that use lots of SRL16s and assume they will have bad area in an Altera part, even if they don't verify this...)
0 Kudos
Altera_Forum
Honored Contributor II
1,700 Views

For Altera,Cyclone is my first choice. When area is the most goal.the balance between logic and register is importan. in another hand,this make the design more interesting.

0 Kudos
Altera_Forum
Honored Contributor II
1,700 Views

I would bet on Patent.

0 Kudos
Altera_Forum
Honored Contributor II
1,700 Views

Hello Avatar, 

 

I have asked about this problem in other topic of this forum. 

 

http://www.alteraforum.com/forum/showthread.php?t=21633 

 

I want to know if you have patented that component or if you have solved this problem in other way. 

 

Thank you very much for your attention.
0 Kudos
Altera_Forum
Honored Contributor II
1,700 Views

I agree with you! 

 

 

--- Quote Start ---  

 

To be honest, I think the SRL16 looks better and would provide better area. Yet I've converted many design with them(especially DSP designs) and have yet to see one where they had an area advantage. I admittedly have always been surprised by this, but have seen it time and time again. I'm sure such designs exist but don't know about them and doubt if they're common. (What I am sure is common, are there are a lot of X designers that use lots of SRL16s and assume they will have bad area in an Altera part, even if they don't verify this...) 

--- Quote End ---  

0 Kudos
Reply