[Gllug] Two Questions

[t.clarke]

Nix asked if TFT screens refresh in any way  !

I have no idea whether a pixel stays switched 'on' or has to be constantly
refreshed,  but presumably the electronics that receive and decode the
analogue signal from the VGA card either:
a) reswitch each pixel every time a new 'scan line' is received from the VGA
   card, or
b) are clever enough to recognise that a given pixel has not changed state from
the previous scan-line and leave it alone  ??

I noted that on a box at home with a particular 'old' vga card operating in
'dumb' character mode (low res) the TFT screen will from time to time display
slight fuzziness on some characters where individuals pixels at the very edge
of the characters are being switched rapidly on and off.  Not sure of the cause
of this, whether jitter inn the power supply to the screen or jitter in the
analogue signal from the card; but it would seem to indicate that the screen
pixels are being constantly 'refreshed' at the scan-rate of the vga card.


Tim
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