Posted on February 01, 2013 at 12:06Yes it might looks is fast, but actually is mostly tricks. What i do is selectively update
very small portions of the screen very fast, and keep track of LCD current state in RAM so i don't have to do unnecessary refreshes.
I try something similiar with the MM4 board.
While the calculation of a full 1024 points spectre takes about 10ms (including some post processing), it takes about 200ms to put to screen, covering less than 1/3 of the area.
That seems far too much, and as there is no DMA support, that is hardly workable.
Reducing the screen area that requires update is the only solution.
To be honest i have never worked on a project
where some real time stuff was displayed - like video. I would assume some very wide
and fast bus is needed - probably 16 bits is the absolute minimum.
They have specialized logic to deal with that. Either it is explicitly a microcontroller, or similiar on-purpose logic. This remembers me on the old days, where PC's had character displays, which worked the same way. The processor wrote the ASCII characters to a (shared) RAM, and a independant logic cyclically read it out, passed it through a character ROM, and serialized the ROM output stream to the screen. This concept has not changed too much for modern GFX cards, but became much more sophisticated and complex...
To something completely different:
this forum software sucks !
