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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...
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Altera_Forum
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20 years ago

Mike, i endeed too had the idea that there is a problem with the timing. so i connected one of my debug output pins directly to the rxd input pin of the uart to see what enters the uart but again a perfect signal.

we have checked the settings of the uart to see if the OS does the right stuff.

The nios uart now gets remove in this application by an ip core developt here that is capable to handle multi master, self arbitrationing, ... and runs at 16MBit on the same targets as the uart.

But we have some equipment left that needs this uart. This morning i had found the sources of the uart, but currently no time to setup signal tap to dig into this uart. so no idea if there is a signal filtering on that rxd line and how the startbit detection works and when the uart samples.

I want that uart working to have in my mind that i can use it in the future again. so i will investigate as soon as i find some time for this. currently the solution with the uart is useless for an industrial enviroment. but in the current app the uart was temporarily until our ip was available.

Michael Schmitt