Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Altera_Forum
Honored Contributor I
1,113 Views

Using IDT71V416 as 16-bit RAM

At some point I removed the Nios I dev kit and I went to recompile my design yesterday and it couldn't find the IDT71V016 RAM device. I looked at out board and noticed that we use the 71V416, not the 71V016. I asked our hardware guy and he said that SPOC Builder assumes you are using two 71V416s if you add them to your design so we kind if kludge it into working by using the 71V016. Is there a way to use the 71V416 as a 16-bit device? Do I simply need to go into the .ptf and change all occurences of 32 to 16? Why isn't this an option in SOPC Builder? Is it un heard of to use less than 1M of memory?

0 Kudos
3 Replies
Altera_Forum
Honored Contributor I
47 Views

I added the ram as user logic  

(remark one userlogic for both ram chips,  

this is necessary to get one block of memory for system library properties) 

 

 

PORTNAME WIDTH DIRECTION SHARED TYPE 

address 19 input yes address  

write_n 1 input yes write_n 

read_n 1 input yes read_n 

data 16 inout yes data 

chipselect_n 1 input --- chipselect_n 

be_n 2 input yes byteenable_n 

 

 

I added external logic (one not and two ors's) to generate the 

two different CS signals 

 

SRAM_CS0_N = SRAM_CS or A19 

SRAM_CS1_N = SRAM_CS or (not A19) 

 

if you want to use only one ram chip, then reduce address to 18 and remove 

external logic.
Altera_Forum
Honored Contributor I
47 Views

Dave, 

 

The reasoning is that we cannot possibly test every permutation of RAM available. Instead the we provided pre-fabbed support for the devices on our development boards, and then the I/F to user logic (now Component Editor) to add a custom interface that has the exact width/depth/timing settings that you need.
Altera_Forum
Honored Contributor I
47 Views

Fischer & Jesse, 

 

 

Thank you both for your help. I'll try out the user logic route.
Reply