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I suspected the baud rate and slowed it down from 115200 to 9600 baud. I changed this in both qsys and putty. I dont think i need to change this anywhere else, correct? the ftdi chip layer would be transparent, right? And, wouldnt need a specific rate.
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The FTDI device is a USB-to-UART, so when you change the baud rate in Putty that change is communicated to the FTDI device, and the baud rate is changed on the TXD/RXD signals to the FPGA.
I'm not sure why you changed the baud rate in Qsys. A UART should have control registers that set the baud rate, and so you would need to change the software that initializes the baud rate to set the baud rate divisors. But perhaps Qsys allows you to set the default divisor values. Either way, if there is are baud rate divisor registers, you need to make sure your software configures them correctly.
The quick-and-dirty test that you have the baud rate correct is to SignalTap II the UART TXD/RXD traces and trigger on the falling edge of either of those signals. Use Putty to send a character and trigger SignalTap II. Then use NIOS II to print "Hello World!" and trigger SignalTap II. If your bit timing is wrong, then you'll know your baud rate setup is wrong.
Cheers,
Dave
Honored Contributor
