Desert Online General Trading LLC
Dubai, United Arab Emirates
Desert Online General Trading LLC
Dubai, United Arab Emirates
This board is meant to be used with the Mojo FPGA development board. Use this board to add two HDMI ports and 32MB of SDRAM to your projects! By default, one port is setup as a source (output) and one is a sink (input). However, they can both be changed with solder jumpers. The ports are capable of resolutions up to 720p at 60 FPS, 1080i at 60 FPS, or 1080p at 30 FPS. Tutorials for using the HDMI ports and SDRAM are provided by Embedded Micro.
J**F
Does seem to generate HDMI signals following the tutorial
I did succeed in going through the tutorial and getting a nice HDMI test pattern to show up at 1280x720x60. One cheap HDMI monitor didn't like the signals and just reported invalid format, and another nicer monitor was very happy to display it. I did have a lot of fooling around to get the clock generator to run on Win 10 64-bit, and ended up just running the core generator/clock generator directly from the Xilinx tools and importing the generated code. When run from the Mojo IDE, it seemed to always use an invalid temporary directory. I also did succeed in getting the camera/hdmi sample project included with the Mojo IDE to work too, simply by building the project (which seems to run at about 640x480x30fps, below the minimum HDMI pixel clock rate), although it takes 60 seconds to "warm up" before the picture is stable. I suspect this is a camera issue not an HDMI issue. It tried to get 1920x1080x30p showing a test pattern, and initially nothing. I eventually hunted down the official timings, and adjusted the frame height and width, but still no image. A little investigation of the code, found the HDMI_Encoder used only 11 and 10 bits for the width and height, which at 1920x1080 + the blank zones, would overflow the counters. After increasing the sizes to 12 and 11, the FullHD display worked. The Mojo board FPGA is not capable of generating 1920x1080x60p TMDS signals. To make 640x480x60 work, I had to set the 3x divider for the HDMI_Encoder, as the Xilinx tools seem to always try and optimize the PLL clock generator for a 25 Mhz pixel clock and incorrectly reduces the clock multiplier to a value too low for the PLL to use, giving a build error. I don't know why Xilinx doesn't just fix the Win10 issues in their older development tools, as it makes me question if investing my time into the Altera/Intel FPGA ecosystem wouldn't be a better learning investment. Win 10 is not about to vanish and lots of people still use the older Xilinx parts. I'm fairly pleased with Embedded Micro's HDMI board, even though everything isn't perfectly smooth. I'm not a highly experienced FPGA designer (I am a highly experienced software designer), but after a couple days fooling around can make 1080p HDMI video signals. I also understand HDMI signals enormously better than before adding this module, and feel I still have lots of learning value yet to go. Seems like thirty five bucks well spent.
