Forum Discussion
Altera_Forum
Honored Contributor
13 years agoIf your 'shared memory' blocks are 'tightly coupled data memory' on the slave cpus (it probably makes sense to dedicate the second port to one of the masters), you do need to ensure they are set to return 'OLD_DATA' during concurrent read and write.
For OLD_DATA to work they must use a single clock. Qsys has an explicit option for single clock - which works ok. SOPC builder will infer a single clock under some circumstances, but not if one of the masters is a Nios cpu (because it qualifies the clock). In this case if you tick 'OLD_DATA' the request is silently ignored.