Baud rate problem with VHDL UART

Pluto/-II/-3/-P boards

Baud rate problem with VHDL UART

Postby mike_ » Tue Jan 05, 2010 6:29 pm


I'm trying to change the baud rate on one of my devices (Pluto-II based) from 115200 to 9600. This is not working and I can't figure out why.

Here are the facts:
* I'm using the VHDL version of the UART that Jean provided here in the forum.
* I read that the programming pins have an issue with slower bauds, so I am using different pins (76 & 77) for the serial port.
* The code and the hardware work great as long as the baud in the UART code is 115200. I change the baud parameter to 9600, set my hyperterminal to the same setting, and I get no response from the device.
* I hooked an o-scope to the serial pins and my computer is definitely putting out 9600 baud.

Any one have any experience changing the baud rate in this code? I've gone through the math in the code and it looks solid. I don't see any reason why the baud rate can't be changed just by changing the baud variable. Any help would be greatly appreciated.

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