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Hi Everyone,
I am currently using a nios ii cyclone 1 epc120 development fpga for an embedded application. At present I have the Altera Avalon UART set to a baud rate of 115200 within the SOPC builder. However, I need to increase this baud rate by at least a factor of 2. Does anyone know if this is possible using this FPGA? or do I need to upgrade to a different board? Cheers.Link Copied
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Yes, you can change the baud rate in SOPC builder. You can also make it adjustable by the embedded software.
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Thanks for the reply.
I know you can adjust the baud rate in SOPC builder but when I open the drop down box 115200 is the highest speed. Is there another way to increase this?- Mark as New
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1 -If you configure the UART such as to have a run-time programmable baud rate, you can program a divisor into the divisor register after power-up. See this document:
http://www.altera.com/literature/hb/nios2/n2cpu_nii51010.pdf There are two other options I can think of which would obviously be unsupported: 2 - Edit the "class.ptf" file found at "C:\altera\90\ip\altera\sopc_builder_ip\altera_avalon_uart". Look for this description for the baud combo box:
COMBO baud
{
title = "Baud Rate (bps): ";
id="baud";
values="115200,57600,38400,31250,28800,19200,14400,9600,4800,2400,1200,300";
editable = "1";
DATA
{
baud = "$";
}
}
Then obviously modify the values line to add your desired baud rate in there. I can't promise this is going to work. You may also have to modify the accompanying "em_uart.pl" perl script. Just do a search on baud in that file and you'll see where to modify it. 3 - The final option is to generate your SoPC system with the undesired baud rate. Then hand modify the generated HDL file to change the divisor. There should be a line somewhere like "assign divisor_constant = X" where you would calculate and replace X with the correct divisor rate. Have fun, Jake
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Awesome. Thanks Jake. Much appreciated.

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