It's very complicated. Without getting into the details of I2C EEPROMs and stuff like that, the KNJN boards work by using the 8051 controller in the FX2 USB chip to implement both the programming protocol and the communications protocol. They have simple example applications in C that run on the PC and allow you to interact with various lights and buttons on the FPGA pins. However, the details of the 8051 programming process aren't well-documented, so you end up having to run KNJN's programmer application to upload their code to the (volatile) embedded 8051 before you can run your own application code that communicates with the board.
That will have to be reverse-engineered before any true standalone applications can be written for the KNJN boards. It's conceivable that some of the GNU Radio FX2 code can be applied directly to the KNJN boards; I haven't gotten that far yet. There are many simple FX2+FPGA development boards on the market besides KNJN's, but without exception (as far as I can tell) they are all produced by mom-and-pop development houses who believe, religiously, that by leaving their programming protocols and 8051 code undocumented, they are actually *adding* value to their products. -- john, KE5FX > > Right; 'program' was a poor choice of words. My concern was more > > about how to get data off the board. I know it's customary to use a > > separate JTAG connection for programming, but if you can do both > > through the USB port, it seems like an obvious way to go. > > Beware. At least some of the FPGA boards with a USB connector > only use it > for programming and power. The USB signals usually go into a > tiny micro. It > knows how to program the FPGA but there isn't any simple way to > use it as a > data path. > > I could easily have missed something wonderful on newer board. I > do remember > being surprised when I figured that out the first time. > > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
