This week was mostly research for the video pipeline, and I began working on the Qt application for the linux side of the project.
The video pipeline for the Zynq uses the AXI VDMA core to transfer data out of the framebuffer which is stored in the Zynq’s memory. (The PS and the PL share the same memory.) A video timing controller creates the pulses for vsync, hsync, etc for the HDMI phy.
The main application will run with Qt and draw to the framebuffer. I need to test this, but petalinux (Xilinx’s linux distribution) has finished drivers for the AXI-VDMA system, so as long as I followed the spec correctly Qt should be able to draw to the hdmi output without any real setup. This is tricky and might be very unreliable at first. The Qt application is multithreaded C++ and will do basically all of the complex work for the synthesis, including envelopes, wavetable selection/loading, video output, reading inputs from encoders, and voice allocation.