The design runs on the FPGA Teletext board. Vunit for unit tests (testbenches only completed for some modules so far).No vendor-specific code (except dual port RAM, PLL and high-speed I/O buffers).
Parameterised design enables design tweaks without any programming knowledge. Level 2.5/3.5 store function for applying enhancements to Level 1.0 pages. Page selection via number keys, up/down buttons, and Fastext keys. Reveal button displays and hides "concealed" page content. Mix function enables/disables the display of background colours (note that this board does not display the video portion of the composite video signal over HDMI). Power-on page number selection via DIP switches. Alpha Black enable switch for selecting between adherence to the original specification or compatibility with certain modern teletext services. High resolution 1280x720 mode also available - see feature/720p branch. Resolution selection via DIP switches: 720x576 or 800圆00 at 50Hz or 60Hz (640x480 possible with minor code modifications). 
Selected Level 2.5 and Level 3.5 display features implemented - CLUTs, default row and screen colour, black background substitution.
#Teletext number generator
A teletext decoder and display generator in VHDL for FPGAs.ĭetailed descriptions of how the various modules work can be found on my blog - Nick's Electronics Blog.
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