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How many bit word for sram?

Altera_Forum
Honored Contributor II
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I would create an sram with megawizard plugin manager. The data input of sram is one bit std_logic, and the q output is one bit std_logic. 

The sram that i have on my cyclone 2 is 512 Kbye (256K * 16 bits). 

What i must write in the megaplugin manager in the window in this link? 

http://img15.imageshack.us/i/rambmt.jpg/ 

 

How many bit words?
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Altera_Forum
Honored Contributor II
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How many do you need?

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Altera_Forum
Honored Contributor II
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i don't know. 

Can you do an example? 

If i need all memory?
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Altera_Forum
Honored Contributor II
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--- Quote Start ---  

 

The sram that i have on my cyclone 2 is 512 Kbye (256K * 16 bits). 

What i must write in the megaplugin manager in the window in this link? 

 

--- Quote End ---  

 

 

There is probably some misunderstanding. As far as I know cyclone 2 (http://www.altera.com/literature/hb/cyc2/cyc2_cii51008.pdf) does not have 256K * 16bits (~ 65,000,000 bits) on-chip memory. The EP2C70 is the largest device with a total of 1,1520,000 RAM bits. 

 

In the assumption that you want to use on-chip memory you can of course only use what is available. 

 

In the Megawizard you can specify the bit-width of the memory. In your case this is '1'. For "How many 1-bit words of memory" you should specifiy the amount of these words that you need. In your form you specified 256 words. This means that you can address your memory with 8 bits (2^8 = 256). 

 

Hope this helps
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Altera_Forum
Honored Contributor II
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I have an Ep2C35 

De2 User Manual 

sram 

 

·  

512-Kbyte Static RAM memory chip 

·  

 

Organized as 256K x 16 bits 

· Accessible as memory for the Nios II processor and by the DE2 Control Panel 

 

Memory Data Sheet 

The issi IS61LV25616 is a high-speed, 4,194,304-bit static 

RAM organized as 262,144 words by 16 bits. It is fabricated 

using issi's high-performance CMOS technology. This highly 

reliable process coupled with innovative circuit design techniques, 

yields high-performance and low power consumption 

devices. 

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Altera_Forum
Honored Contributor II
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--- Quote Start ---  

I have an Ep2C35 

De2 User Manual 

 

--- Quote End ---  

 

 

 

You are refering to off-chip memory. The "memory compiler" in the MegaWizard is for on-chip memory. This means the memory blocks that are in your Cyclone II Fpga. You are refering to the off-chip SRAM module on your DE2 board. 

 

You can directly address your SRAM from your FPGA (but not via the MegaWizard), or you can add this SRAM very easily in the SOPC Builder. The university program ip cores (http://www.altera.com/education/univ/materials/ip-cores/unv-ip-cores.html) already provide prepared interfaces of the SRAM on the DE2 board in the Avalon fabric.
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Altera_Forum
Honored Contributor II
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I'm afraid you are not doing this the correct way round... 

First you should describe what you want to do. Then you can determine how much memory you need, and depending on available resources you can decide if you are going to use on-chip memory or the external RAM.
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Altera_Forum
Honored Contributor II
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thanks for your help

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