False values in Quartus In-System Memory Editor

Sep 05, 2005 6 Replies
S

Hi.



I have a problem with the In-System Memory Editor in Quarts II 4.1. I can read the memory contents and get the correct values when I do not write the memory before. But when I write any values (including the old memory contents) to the memory and read thereafter, I get false values. This only happens when using ram, when using the memory editor on LPM_CONSTANT, I always read the correct values. I verified that no logic of my design is responsible for that, by creating a memory from the MegaWizard Plugin Manager and setting the memory as the top level module, thus no other logic is there besides the memory.



Can anybody help?



Sebastian Schmidt.


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A

How do you read and write the memory?In simulation ? Or in real hardware (How did you debug that) ?

Rgds Andr=E9

Sebastian Schmidt schrieb:

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S

Hi.

I read the memory over the JTAG interface with the In-System Memory Content Editor.

Sebastian.

Am 05.09.2005, 17:30 Uhr, schrieb :

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A

So where does your write enable for the memory come from ? Directly from pin or is it an internal logic ?

Rgds Andr=E9

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S

The wren port is set to 0, so that no writes occur out of the logic.

Sebastian.

Am Tue, 06 Sep 2005 08:45:28 +0200 schrieb :

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A

But you said in your post before that you write to the memory?

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S

Yes, in Quartus I instanciate a 1-Port RAM from the megawizard plugin manager. There I select, that I want to be able to access the memory from the Quartus In-Systme Memory Content Editor. In the design you see the memory as a 1-Port memory, the second port is not seen in the Verilog source, it is inserted on compile time by Quartus. I have disabled the write enable port of the first port, the write enable port of the second port is handled by Quartus.

Am 06.09.2005, 14:20 Uhr, schrieb :

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