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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

Good morning,

of course we are using USB Blaster Rev.B

I do not think that a "slow" Blaster can be the reason for wrong data being received by the uart. we started the investigation because we noticed wrong data beeing received. To find the source if the OS has a bug or the uart realy delivers wrong data.

within signaltap if i trigger on falling edge of chipselect and rising edge of read_n with adress = 0 i get the data the uart transfers to the nios by having a look at readdata. as we see here wrong data the os is not the source. but why does the uart deliver wrong data ? the serial stream is perfect no jitter and 50:50 duty cycle.

And without a blaster connected we also have the wrong data.

Michael Schmitt