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TSW1405EVM - as development platform

Other Parts Discussed in Thread: ADS62P49

I posted this elsewhere, not sure of the right place.

I'm interested in Software Defined Radio, [receive only] in HF bands. I was looking at FPGA boards with FMC connectors, but now I've noticed the TSW1405EVM [$99] with a Lattice ECP3 FPGA.  I would like to combine this with the 2-channel 250MSPS ADS62P49EVM [$299 - total cost approx $398]. Is this a viable combination?

Although both TI and Lattice are advertising the TSW1405EVM on your respective web sites, I'm finding it hard to track down details. Since I'd be using the FPGA as a Digital Downconverter (DDC) or CIC filter, rather than just verifying the operational parameters of the dual-channel ADC, I'd have to write my own code. Will either TI or Lattice be supporting this module as a general-purpose Development board?

  • Hi,

    Your post from elsewhere got moved to this forum as well, and I see you have a response to that one.

    I might want to add that while the TSW1405 and ADS62P49 *are* a viable combination (The TSW1405 was made to capture data from the ADS62P49 EVMs and others) the TSW1405 is not meant to be a *general purpose* development board.  You would be on your own for developing your FPGA code for the TSW1405, but Lattice has been taking the source code from our TSW1405 and extracting the interface to the ADC out of it and making a block of code that you can get from the Lattice website and just instantiate in your design.  That should make the actual ADC interface easy.  So yes, there is support in that sense.

    But please note that the TSW1405 does not include an eeprom to hold your firmware.  in our usage, the GUI for the TSW140x will push the firmware into the FPGA at run time for each type of ADC that you choose.  When you power cycle the FPGA, the firmware is gone again.  This is nice for a Capture Card like TSW1405 because we never have to worry about shipping a board back to Dallas to be re-programmed every time we come out with new EVMs.  When a new revision of our firmware is available we just put it on our website.  But you would have to load the firmware every time when you develop your code.  The Lattice programming pod can conenct to the TSW1405 but you would need to solder some 0-ohm resistors onto the board to connect the JTAG port for programming, and remove some other resistors to disconnect the USB chip from the JTAG programming port.  The physical design database (schematics, layout) are on the TI web for the TSW1405.    Also, the TSW1405 gets its power from the USB port of the PC.  If you want to power the TSW1405 on your own without a USB connection, there are loops to clip on to for power from a bench supply if you wish.  Again, consult the schematics and/our layout files from the web.  There *are* a few spare jumpers, LEDs, and an extra pushbutton switch that you could use for your own purposes.  And if the FPGA turns out to be too small for your code down the road, I *think* there is a version in the same package footprint but more gates and memory that you could have assembled onto the board. 

    Regards,

    Richard P.

  • Thank you, Richard.

    For a final product, it would be... useful... to take the code for the current Lattice chip, and use it to verify functionality of the ADC front end. However, you have pointed out some interesting quirks in the nature of the TSW1405. Power [and clock] for the 2 boards are design areas not to be glossed over.

    Still, as a setup, it is remarkably cheap. I guess you get what you pay for: I'll have to think hard on whether the shortcuts outweigh the cost convenience.