TSW1200EVM Baud Rate

Hi,

I presume you are using a folder of Matlab code from TI to control the TSW1200.  If so, in the file initSerial.m you will find the line of code:

objSerial1.BaudRate = 460800;

You may change the value assigned for the baud rate to 115200, 230400, 460800, or 921600 - or at least  those are the options that are proprogrammed into the standard TSW1200 User Interface.  We do not recommend the highest setting as it is not reliable.  The fastest reliable baud rate setting in most cases is 460800, although I have seen some machines that seem to benefit from a lower setting.

The data link between the FPGA and the USB chip on the TSW1200 is a simple 2-wire UART, and there is no flow control implemented on this link.  The rate of this UART is what we are setting when we change the UART baud rate.  In the FPGA the UART is simply a block of UART code that Xilinx has made available.  From the TSW1200 board to the PC is a USB cable, and on the PC side we are running virtual com port software to make the USB port to the TSW1200 look like a simple com port.  The UART rate is a parameter for the com port.

The baud clock for this UART link is sourced by the TUSB3410 USB chip at the edge of the TSW1200 card.  When the software for the User Interface (either the Labview based User Interface or the Matlab code) accesses the com port to the TSW1200, there is a data parameter for the baud rate and the device drivers on the PC side handle telling the USB chip what baud rate to use for the UART side of the TUSB3410.  The TUSB3410 creates the baud clock to the FPGA accordingly and the FPGA simply uses that baud clock.  There are no registers in use in the FPGA anymore to set UART rate at all - it just gets it from the USB chip. 

There may be other choices available for setting that UART baudrate than the four that we have listed, but i do not know what other choices may be permissable.

Regards,

Richard P.