On Sun, Aug 20, 2006 at 09:52:01PM -0700, James Richard Tyrer wrote:
> >Most displays cannot change mode. High quality computer monitors are
> >fixed mode. TVs are fixed mode. The multi-sync monitors are the
> >anomaly. Those LCD displays aren't really multi-sync, the panel has
> >a fixed resolution. But the brain-damaged pee-seas expect a multi-sync
> >monitor, so the LCDs add some sort of scan converter, which raises
> >the cost of the display, and for what? So you can have a crappy
> >looking display if you aren't using the native resolution of the panel.
>
> Point taken AFA LCDs are concerned. However, I don't think that the
> hardware scan converter adds a lot to the price and crappy BIOS and boot
> display isn't a big issue. OTOH, a QVGA LCD doesn't need an
> interpolating scan converter to display VGA.
>
> However, the bootstrap problem remains. If the Board can't read the
> information from the monitor, it needs to be able to display VGA on the
> monitor for configuration.
Not all fixed-frequency displays can sync to a VGA mode. Tim and I
have been discussing this off-list so as not to take up everybody's time,
but basically there needs to be an optional external tool that plugs into
the SPI pins on the accessory header, which will allow the ASIC to power up
in an arbitrary mode -- which may or may not be VGA, but it's whatever the
display can sync to. There can be other kinds of configuration or debug
tool that plug into the SPI port, but what this one has is a set of about
120 DIP switches, which allow arbitrarily locking in _any_ mode that the
ASIC is physically capable of generating at power-up time, and disabling all
mode-change commands from the host. That way, some obscure program that
thinks your monitor is capable of VGA modes can't blow it up.
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