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Valued Contributor III
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Using OLD_DATA with 'tightly coupled memory'

We are moving a project forward to quartos 14.1 (and new hardware). 

The qsys page for 'On-Chip memory' now lets you select single clock in order to get true dual port and OLD_DATA. 

However there is a comment that 'Tightly Coupled Memory operation requires dual port & dual clock sources. 

 

Lack of 'OLD_DATA' gave us grief on 9.1 and we fixed it by editing the memory wrapper. 

 

Does anyone know if this is still a bug/restriction in qsys, or is the comment wrong. 

 

IIRC the tightly coupled memory uses the 'address_stall' to hold the output data during 

pipeline stalls. This seems to be defined for the Cyclone V we are targetting.
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Valued Contributor III
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Where did you see the comment on the Tightly Coupled Memory ....?  

 

You can just set dual port and single clock mode. It should work with old data.
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