simulation problem

[john]

Hello,

I am using a Spartan chip to read a 48 bit of data from SDRAM then
serialing it out at the rising edge of the clock. I am getting some
problem in the data. I want to simulate my VHDL code in MODELSIM or
ISE but I can not simulate SDRAM which provides the data to my VHDL
code.

I have a hex number file which I download to physical SDRAM before I
started reading from the SDRAM. The question is that how can I read
that hex formatted file using MODELSIM or ISE and made my VHDL code to
read it and serial out the 48 bit data.

Please advice!

John

 

[Mike Treseler]

I am using a Spartan chip to read a 48 bit of data from SDRAM then
serialing it out at the rising edge of the clock. I am getting some
problem in the data. I want to simulate my VHDL code in MODELSIM or
ISE but I can not simulate SDRAM which provides the data to my VHDL
code.

If you are using a xilinx board and sdram controller core
I would focus first on simulating just the entity doing
the custom read cycles and shift register.
The sdram core probably works fine.

-- Mike Treseler

 

[john]

Hi,
Yes, thats true but inorder to simulate the entity doing custom read
cycles and shift register, I need data from the file.
John

 

[Mike Treseler]

Hi,
Yes, thats true but inorder to simulate the entity doing custom read
cycles and shift register, I need data from the file.

You need that for your final testbench.
You don't need it to verify that the
code you wrote is wiggling the interface
waveform just right. I expect that it isn't.


-- Mike Treseler

 

[Ben Jones]

I want to simulate my VHDL code in MODELSIM or
ISE but I can not simulate SDRAM which provides the data to my VHDL
code.

You can, if you have a model of an SDRAM device. You used to be able to get
these for free (I have one somewhere from Micron). Try google.

Of course, you then need to get your initialization data into it when your
testbench is starting up, but that's not so very hard to arrange.

Good luck,

-Ben-

 

[ALuPin]

Use a SDRAM VHDL model, for example Micron.

Rgds
Andre

 

[john]

Hi,

Please forget that I am using SDRAM. I need alot of 48 bit numbers
that I want to serial out. So, now I need a file that I can use for my
serial out module. So, how can I read that file?

John

 

[Mike Treseler]

Please forget that I am using SDRAM. I need alot of 48 bit numbers
that I want to serial out. So, now I need a file that I can use for my
serial out module. So, how can I read that file?

I would use an array of vhdl constant
vectors instead of a text file.

-- Mike Treseler

 

[Andy]

I would use an array of vhdl constant
vectors instead of a text file.

-- Mike Treseler

And you can initialize that constant array with a function to compute
the values if you so desire.

Andy