Re: LCD64 Update /Help

From: Hársfalvi, Levente (levente_at_terrasoft.hu)
Date: 2001-03-09 09:11:09

Hi!



> The next step is to introduce the standalone powerpack. I'm intending to use
> some decent sized NiCads to provide the 5volt supply.  From what I've read
> on the net, 5V should run most of the chips, and in the short-boards (eg
> C64e and C64b3) the VIC apprantly doesn't need the higher voltage.

Just remember: although the new VIC-II needs no additional power supply
voltage, the new 8580 SID still does (9v DC).

(It's a hard one; you'll either need 9v accus or have to generate the 9v
from 5v using some switching mode regulator chips, like the TL497
(...bad efficiency in step-up configuration)).

> Two issues remain:
> 1) TOD signal - I'm hoping to use a tuned 555 timer to run at 50Hz

Probably yes, and if you use the NE7555 (CMOS 555) it'll consume less
current.

(If the 50Hz timer is needed at all).

> I'm also assuming the short boards use less current because of the newer
> design /number of chips. Is this assumption correct?

It must be true (much less TTLs, and newer custom chips with less power
consumption). The new VIC and SID takes much less current, that's for
sure.


Best regards,


L.


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