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Explorer
Explorer
293 Views

DDR3 IP, mig_7seriess:4.0. during read

Is there a bug with the DDR3 IP, mig_7seriess:4.0.

I send in 4 app_en during app_rdy=H with a read command to the memory controller interface and most of the time I get back 4 app_rd_data_valid=H.

But sometime I only get back 3

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13 Replies
Explorer
Explorer
262 Views

Re: DDR3 IP, mig_7seriess:4.0. during read

I ran a continuous loop where I keep reading the same 4 address in DDR3 memory.

My sequence is to send 4 app_en when app_rdy=H then wait for 4 app_rd_data_valid then repeat this sequence.

 

after a while ( a few second) the memory controller doesn't return any app_rd_data_valid signal

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Moderator
Moderator
249 Views

Re: DDR3 IP, mig_7seriess:4.0. during read

Hello @tchin123,

 

Please upload your waveform so it can be analyzed.

 

Thanks,

Cory

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Explorer
Explorer
246 Views

Re: DDR3 IP, mig_7seriess:4.0. during read

I found the issue, it was subtle but since the refresh occur so often, even though the rdy=h it drop the same time which coincide with my en=H

Explorer
Explorer
237 Views

Re: DDR3 IP, mig_7seriess:4.0. during read

How often does XiIlinx memory controller DDR3 refreshes because I noticed that APP_RDY occur very often periodically.

I assume this is because it is refreshing the memory. It was measured (ILA) at 977 ns.

 

Is this the refresh rate at 977 ns. This is very fast. I thought it is normally it is 7.8 us?

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Moderator
Moderator
230 Views

Re: DDR3 IP, mig_7seriess:4.0. during read

Hello @tchin123,

There are only a few reason we de-assert APP_RDY as found in PG150:

app_rdy_low.PNG

Thanks,

Cory

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Explorer
Explorer
220 Views

Re: DDR3 IP, mig_7seriess:4.0. during read

The app_rdy from the ddr3 memory controller is pulsing continuously at a period of 997 ns when there is no user activity.

pulse is 15 ns low.

Since I'm not generating any request this pulsing should come from the memory controller during refresh mode. Where else could cause this? It is very frequent.

 

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Moderator
Moderator
218 Views

Re: DDR3 IP, mig_7seriess:4.0. during read

Hello @tchin123,

Please provide your waveform so we can look into this issue.

Thanks,

Cory

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Explorer
Explorer
203 Views

Re: DDR3 IP, mig_7seriess:4.0. during read

Attached is waveform file.

Top is full view and bottom is zoom within a period of app_rdy which is 977 ns.

When there is no user request the app_rdy remains the same

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Explorer
Explorer
188 Views

Re: DDR3 IP, mig_7seriess:4.0. during read

here it is. I have to remove the wdb extension otherwise it complains

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Explorer
Explorer
166 Views

Re: DDR3 IP, mig_7seriess:4.0. during read

i have to send in public message screen the private one doesn't have what you circle.

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Explorer
Explorer
159 Views

Re: DDR3 IP, mig_7seriess:4.0. during read

Here is the ILA file.

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Explorer
Explorer
158 Views

Re: DDR3 IP, mig_7seriess:4.0. during read

if you think a simulation file is better

It will take an hour, I will do it tomorrow, let me know

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Explorer
Explorer
127 Views

Re: DDR3 IP, mig_7seriess:4.0. during read

Hi, based on the request and what I send to you, any idea why the interface ddr signal app_rdy pulses so frequent?

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