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Altera_Forum
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17 years ago

Simultaneous Write/Read to on chip dual port RAM

Obviously simultaneous writes will cause problems. In our case, one Avalon Master is reading while the other Master is writing. So, the question is, will simultaneous write and read of t...
Altera_Forum's avatar
Altera_Forum
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13 years ago

Although there is an 'old data' / 'don't care' option, I think we've discovered (the hard way) that this gets ignored (in 9.1sp2 at least) because both clocks are specifed - even when they are identical.

Quartos 12 has an extra 'tick box' for 'single clock operation'.

The http://www.altera.com/support/kdb/solutions/rd04172006_685.html?gsa_pos=2&wt.oss_r=1&wt.oss=altsyncram%20parameters

is just a lame excuse!

If you request OLD_DATA then it shouldn't be discarded, but constrain the types of memory that can be used.

Without OLD_DATA you get the old or new copy of each bit, changing randomly with different silicon and different builds of exactly the same vhdl.