In our last article we described some ways to enhance the display of a text scrolling smoothly.
We actually tried several possibilities of settings for the scrolling text and finally found a convenient one (as shown on the video above).
We did some major improvements concerning the speed of the code on the card succeeding in speeding it by a factor of 5. We deemed that a major issue of that program lays on the access time of the memory. Indeed it takes more than 20 seconds to write an ILDA file of a tweet from the ram to the flash. Samuel suggested that we could use a socket to directly send the ILDA file from the python script to the C program in charge of the FPGA communication. In fact, with such a strategy we would avoid the slow speed flash access and be able to send a tweet to the laser around 30 seconds after its validation.
In addition we’re going to add some bit stuffing to make the frames equally populated in terms of points so as to assure a constant frame rate. You can easily notice that disturbing effect on the video above.
In parallel, we’re getting familiar with the DMX protocol and are working on the DMX board.
We haven’t forgotten the software fifo between the C program and the FPGA. We deemed that a zeromq socket would be a interesting solution and we are currently working on it.
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