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Beginner
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Is the IrDA UART setting the same for the TX and RX signals?

I'm trying to use IrDA UART in Nios II to send and receive signals to an FTDI 232.

I am using the UART setting: 9600bps, none parity, Data Bit 8, stop bit 1.

I can perfectly read the information sent to Nios RX, but the signal generated by the TX UART follows another pattern.

The output signal remains at low logic level, there are 10 pulses where the 8 centers represent the inverted logic level of the original data.

Another problem is the baud rate that is different from what was configured.

In the image two signals are presented, one generated by FTDI 232 (correct) and understood by Nios, the signal represents 4 Bytes, where the first byte is sent back by the NIOS UART .

The signal generated by Nios right represents the original value, but uses a different protocol as IrDA UART configurated in Platform Designer.

Can someone help me with this problem?

 

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3 Replies
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Employee
7 Views

Hi, Can you show me the Qsys design and explain more about the issue to be clear?
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Beginner
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The input and output signals of the IrDA UART core are different, input signal follows the UART protocol but output signal follows another protocol, I believe the difference is necessary to transmit the information through a photoemitter, allowing it to be received by a phototransistor.

For two-way UART communication, the most correct is to use RS232 UART core. My problem has been solved.

Thank you for your interest.

 

 

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Employee
7 Views

Hi, yes it is recommended to use a photot-transistor for isolation.
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