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Altera_Forum
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20 years ago

Nios-II SOPC UART delivers wrong bytes

We use the UART in our Nios-II design that comes with Quartus 5.0SP1 and Nios-II 5.0 We face the problem that sometimes the Uart reports wrong RX Bytes from correct RX streams. The serial str...
Altera_Forum's avatar
Altera_Forum
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19 years ago

Oh ... an old posting from my side ...

we use a multitasking OS that does fast enough switching if an interrupt occurs. even a couple of avalonmasters with 1-2MB/sec and INTs every <50uSec is no problem.

So the software is fast enough. The fact is that we read bytes from the uart that where never transmitted. no errorbit set. we have monitored that with signaltap.

the normal uart is not used any more. there were some other postings here reporting similar problems. we have use a self written uart to get rid of these problems. but even that was only a temp. solution.

Having a short look at the uart source showed us that we do not see any kind of filtering to get rid of spikes .....

Michael