VIDEL PAL/NTSC

[Vincent Rivière]

Hello.

I would like to know how the Falcon TOS 4.04 choses between 50 and 60 Hz
resolutions on RGB monitors. For example, if I switch to the ST-Low
resolution from the desktop, will it switch to 50 or 60 Hz mode ?

On ST TOS, the PAL/NTSC flag was hardcoded into the OS header in each
national TOS. But if I'm not wrong, there is only one international version
of Falcon TOS 4.04.
So on Falcon, does the PAL/NTSC settings come from the country code stored
in the NVRAM ?
What happens if the NVRAM is not initialized, it could lead to wrong
frequency and unusable display, then the user will be unable to switch to
the right mode...

And final question, do the PAL/NTSC settings have some importance on VGA
monitors ?

Thanks in advance.

[Mark Bedingfield]

Post by Vincent Rivière
Hello.
I would like to know how the Falcon TOS 4.04 choses between 50 and 60 Hz
resolutions on RGB monitors. For example, if I switch to the ST-Low
resolution from the desktop, will it switch to 50 or 60 Hz mode ?
On ST TOS, the PAL/NTSC flag was hardcoded into the OS header in each
national TOS. But if I'm not wrong, there is only one international
version of Falcon TOS 4.04.

Correct.

Post by Vincent Rivière
So on Falcon, does the PAL/NTSC settings come from the country code
stored in the NVRAM ?

Yup.

Post by Vincent Rivière
What happens if the NVRAM is not initialized, it could lead to wrong
frequency and unusable display, then the user will be unable to switch
to the right mode...

I'd doubt it as the

Post by Vincent Rivière
And final question, do the PAL/NTSC settings have some importance on VGA
monitors ?
Thanks in advance.

The videl chip in the Falcon is completely programmable, its possible to
have all sorts of odd permutations. The defaults are set by the NVRAM
settings. If its set to UK or EU then it will default to 50hz or 60hz
for US.

Mark

[x***@cix.compulink.co.uk]

Post by Vincent Rivière
I would like to know how the Falcon TOS 4.04 choses between 50 and 60 Hz
resolutions on RGB monitors. For example, if I switch to the ST-Low
resolution from the desktop, will it switch to 50 or 60 Hz mode ?
On ST TOS, the PAL/NTSC flag was hardcoded into the OS header in each
national TOS. But if I'm not wrong, there is only one international version
of Falcon TOS 4.04.
So on Falcon, does the PAL/NTSC settings come from the country code stored
in the NVRAM ?

Yes, I think that's the case. The NVCONFIG.CPX has a checkbox for
'PAL mode'. I presume that if that's not crossed the output will
be 60 Hz RGB.

Post by Vincent Rivière
What happens if the NVRAM is not initialized, it could lead to wrong
frequency and unusable display, then the user will be unable to switch to
the right mode...

Most modern monitors will give a readable display on either 50 or
60 Hz.

Post by Vincent Rivière
And final question, do the PAL/NTSC settings have some importance on VGA
monitors ?

I don't think so.

Regards, /Peter/