Re: Using OLD_DATA with 'tightly coupled memory'

Altera_Forum · ‎03-31-2015

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.

Altera_Forum · ‎10-06-2015

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.