This code is a quick trial of generating VGA coloured text using the RPi scanvideo code https://github.com/raspberrypi/pico-extras/tree/master/src/common/pico_scanvideo
As described in the above reference, it fills the scanvideo_scanline_buffer->data buffer with the pixels to be displayed. A single RAW_RUN is used for 641 pixels, including a black pixel at the end of the run.
It proved not possible to fill the data buffers fast enough to output 640X480x60 scanlines. Therefore a 640x240x60 mode was defined, in which each horizontal row is displayed twice in succession to fill the screen.
At present the code just displays the contents of tbuf[], which is filled with a demo pattern. However the code is only using one core, so it will be possible to use the second core to generate or update the text to be displayed.
A simple test of USB keyboard input has now been added. Keyboard handling has been moved to core 1 as it was glitching the render loop. Keyboard lock LEDs have been implemented.