Re: $D012 values on C64

From: Michał Pleban <>
Date: Thu, 20 Jun 2013 11:34:13 +0200
Message-ID: <>
Hello! wrote:

> And what about disabling the screen? We all accept this when 
> reading from or writing to tape so IMHO we also can bear it when 
> updating the Flash chip. 
> I assume that you do these writings for updating the onboard 
> software once a week, month, maybe year, and not every 5 seconds or 
> so.

I guess not many people use the tape anymore ;-)

I can disable the screen, but reprogramming the Flash for the whole
KERNAL/BASIC/CHAR set takes several seconds. I would rather like to
display to the user some informational messages about what is being
performed, than disable the screen for few seconds and let him wonder
what's happening (which could, for example, lead him to lose patience
and reset the machine thinking it has hung - which would result in
half-programmed Flash, a bad situation).

I tried the raster line trick and it works well - the bytes are written
to the Flash when VIC draws the border and the screen is intact. But
there is another problem, however :-( To write to the Flash, I need
first to erase a 4kB sector, which takes about 25ms (according to the
chip specs). That means that the screen is garbled for about one video
frame per each sector erased, and this cannot be avoided.

Therefore I think I'll just copy the CHAR data to RAM during chip


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Received on 2013-06-20 10:00:54

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