which is better to use : Registers or RAM ?

[Yun Lin]

If you use some memory compiler products of famous company, such as Artisan, Versilicon, you can see the difference.

 

[omara007]

If you use some memory compiler products of famous company, such as Artisan, Versilicon, you can see the difference.

and if I don't use, how can I know the difference ?

 

[zcg]

If you use some memory compiler products of famous company, such as Artisan, Versilicon, you can see the difference.

Excuse me, I don't think you have clear idea of RAM & REGISTER.

Added after 5 minutes:

If you use some memory compiler products of famous company, such as Artisan, Versilicon, you can see the difference.

and if I don't use, how can I know the difference ?

What are you confusing for? For 2K store, just go to use RAM.
According current process, 2K RAM(1T or 6T) is doutbless more efficient then reg.

 

[eeeraghu]

Hello All,

This might be a rookie question compared to the analysis of the above topic, But it would be great if i am solved with it and help ful, my concern is that

The library which we use, do they provides Different ranges of RAM? to instantiate it for our application.

Suppose if iam using a synthesis tool, how can i use the RAM if predefined in the library to a particular application?

In verilog there are few attributes to synthesis the ram/rom modules such as
(*synthesis, ram_dual(and others)*) how can i use these attributes in the real time i mean under some RC tool or DC tool.


Thanking you
Raghu

 

[omara007]

When the memory size is small than 1024x16, the area of register file is small than that of RAM and the peak or average power of regfile is also small than RAM from its report.
Jarod

I managed indeed to cut my storage resources down to only 1 KByte .. which is the critical size, right ? ..
It looks now that I will have to go back to the Registers solution !

No one answered my previous question : what's the difference between the normal registers that u can code in RTL and tell the backend guys to put them close together ( for less routing ) and the Register File supplied by the Foundary ?

 

[eda_wiz]

When the memory size is small than 1024x16, the area of register file is small than that of RAM and the peak or average power of regfile is also small than RAM from its report.
Jarod

I managed indeed to cut my storage resources down to only 1 KByte .. which is the critical size, right ? ..
It looks now that I will have to go back to the Registers solution !

No one answered my previous question : what's the difference between the normal registers that u can code in RTL and tell the backend guys to put them close together ( for less routing ) and the Register File supplied by the Foundary ?

Register files are densely packed cluster of ordinary registers with very optimised layout. If you use verilog registers along with synthesis and place and route tools you may not be able to achieve the same level of integration.

 

[hgby2209]

The memory complier I used has already provide the RAM and register file(not synthesised by synthesizer).
When the memory size is small than 1024x16, the area of register file is small than that of RAM and the peak or average power of regfile is also small than RAM from its report.

PS: the case I try is T-like 0.18 process.

Sincerely,
Jarod

I use Artisan Memory Compiler, but I never got the "register file", could you tell me how to get it, or what's the file's file format, or what's the file extension name?

 

[jarodz]

To Thomson,

I don't know is it legal to post the reports from the memory complier on this forum?
But I can tell you that the memory complier I used is Verisilicon for GSMC 0.18 process.

To omara007,
I agree the whizkid's word. The regfile synthesised by synthesizer may be less optimised than that memory complier provided in the area. But I think it can be archieved by additional APR effort to force them grouped close. From this concern, I suggest it is better to use RAM unless your memory complier can provide regfile.

Sincerely,
Jarod

 

[jiang]

Hi... whizkid

I'm interested in 1-T SRAM.
Can you explain 1-T SRAM architecture and how to work?
Can you share technology material for us?

If you are too consious about power I would suggest 1-T SRAM rather than 6-T SRAM. well I think you should consider the fact that using a RAM increases the testing circuitry(memory bist) and a memory controller... Also testability of the circuit reduces.

Check out Register files(usually used for mid-size memories) from your foundry.
They can be tested with scan chains and more easy to use.


Regards
whizkid

Added after 3 minutes:

2KB ram is the doubtless choice..

??????

 

[omara007]

so guys .. summing up everything .. what's the conclusion for the comparision among :
1- RTL coded Register File
2- Foundry supplied Register File
3- RAM

for the following targets :
1- Power Consumption
2- Performance
3- Testability
4- Cost

given that the size is 1-KB.

I guess we better put this in one table for the best output of the discussion.

 

[stocking]

Of course , sram is the sole choice for 2k storage!
2k is not a small number! register is not a clever choice!

 

[eda_wiz]

Hi... whizkid

I'm interested in 1-T SRAM.
Can you explain 1-T SRAM architecture and how to work?
Can you share technology material for us?

[/quote]

1 Transistor SRAM is patended technology of Mosys. Major foundries like TSMC ,UMC offer customers this technlogy.. you should contact your foundry to check whether they offer this technology.
check the attached paper and the link
**broken link removed**

 

[eda_wiz]

I use Artisan Memory Compiler, but I never got the "register file", could you tell me how to get it, or what's the file's file format, or what's the file extension name?

Artisan Memory Compiler(for generating register files) is available in their website.. did you check?

 

[rakko]

sram is much faster than dram, easier to interface to meaning sram controller design is small and easy to design. DRAM controllers are more complicated. on the other hand, SRAM is bigger in area than DRAM and burns more power than DRAM. In short only use SRAM if your memory needs are small like less than 4096 bits else stay with DRAM.

 

[Yun Lin]

If you use some memory compiler products of famous company, such as Artisan, Versilicon, you can see the difference.

Excuse me, I don't think you have clear idea of RAM & REGISTER.

Added after 5 minutes:

If you use some memory compiler products of famous company, such as Artisan, Versilicon, you can see the difference.

and if I don't use, how can I know the difference ?

What are you confusing for? For 2K store, just go to use RAM.
According current process, 2K RAM(1T or 6T) is doutbless more efficient then reg.

If you use SMIC and GSMC memory compiler, you can find the different.
BTW, I designed SRAM and Register memory for SMIC and GSMC, and I also wroten the spec for them.

 

[bianyh]

RAM is likely be the choice. For 2K Byte memory unit, it is around 16K bits, which is way too many for FFs. Register file is also likely not a choice in this case.
I would recommend to write the design and compare the design area for
RAM
register file
FlipFlops.

Added after 12 minutes:

Why not let people know what the difference is really there?

If you use some memory compiler products of famous company, such as Artisan, Versilicon, you can see the difference.

Excuse me, I don't think you have clear idea of RAM & REGISTER.

Added after 5 minutes:

If you use some memory compiler products of famous company, such as Artisan, Versilicon, you can see the difference.

and if I don't use, how can I know the difference ?

What are you confusing for? For 2K store, just go to use RAM.
According current process, 2K RAM(1T or 6T) is doutbless more efficient then reg.

If you use SMIC and GSMC memory compiler, you can find the different.
BTW, I designed SRAM and Register memory for SMIC and GSMC, and I also wroten the spec for them.

Added after 54 seconds:

Even for 1KB = 8Kb, I will still go for the RAM.
Artisan memory compile is free. Why not download one and compare the result?

so guys .. summing up everything .. what's the conclusion for the comparision among :
1- RTL coded Register File
2- Foundry supplied Register File
3- RAM

for the following targets :
1- Power Consumption
2- Performance
3- Testability
4- Cost

given that the size is 1-KB.

I guess we better put this in one table for the best output of the discussion.

 

[omara007]

Artisan memory compile is free. Why not download one and compare the result?

Would you please give a link to where to get Artisan ? .. I could reach any link to get it for free from.!

 

[eda_wiz]

you need to register in artisan website. once they accept your registration you can download libs.

**broken link removed**

 

[Yun Lin]

Verisilicon memroy compiler is aslo free, but that need you regist.
www.verisilicon.com

 

[funzero]

If your design tend to be portable in defferent process . register is a good choice .for there may be no ram in some foundry line .
if you just stuck at to a single process . 2k ram is good.