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tow port ram read & write problem?

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voidman

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what happended when we read and write to the same address at the same time to a two port ram?
we get the old data or new written data?
 

voidman said:
what happended when we read and write to the same address at the same time to a two port ram?
Click to expand...

Druing the simulation, the most possibility is displaying the XXX in the waveform.

So you need to control the address in the ram controller.
 

It's depend the RAM you use.

When you design a system, it's your reponsbility to prevent read/write

the same entry together.
 

It will depend on the RAM you are using but most of the result will be unknow xxxx

You should add control logic to avoid this kind of situation
 

that's up to timing relationship between read and write,

if read is early few ns than write, then the read data is old

data.

if read is late few ns than write, then the read data is new

data.

if read and write occur almost simutaneous, then result is

undetermined.



voidman said:
what happended when we read and write to the same address at the same time to a two port ram?
we get the old data or new written data?
Click to expand...
 

You can't output read and write address at the same time, even if you use one port, two port or dual port SRAM.

You must notice this key point.
 

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