[sdiy] HA12019 (It's a VU meter chip)

[Batz Goodfortune]

Y-ellow all.
         Speaking of salvaging parts... I've tried to be good. I've tried 
to do this without anyone holding my hand. I'm quite adept at working 
without a net.  But try as I might, I can't find any NFO on the above 
Hitachi chip.

I'd very much like to know if it's got a bar/dot mode like the ol' NSC 
LM391x family. With the addition of an oscillator and an integrator it's 
pretty simple to do a peak average meter by swapping backwards and forwards 
between bar and dot mode. And making the meter chip read 2 different 
sources. Most people don't seem to realize this so I've just put in a few 
lines for anyone who may be bemused by the light bulb that's just switched 
on above their heads.

In fact ye olde 3916 can be muxed up to about 8 separate meters with a bit 
of buggerizing around and such a circus is floating around on my web site. 
I think? Since my web site largely has a mind of it's own I'm never quite 
sure what it's doing at any given time. Sometimes it tells the most hideous 
lies about me. But anyway.

For those who like reading I'll tell you the sordid tail of the HA12019 in 
a paragraph or two. But I'd just like to mention that the previously 
mentioned, ancient intel-type 82x55 just happens to be my favorite intel 
part of all time. They are in fact a 24 bit bi-directional I/O chip With 
the middle port being split into 2 nibbles. But it's entirely programmable 
so you can use it any way you like. It's like having 3 octal D-latches only 
it's bi-directional and can also store in both directions. The reason they 
still make them is because they're just so damn handy.

They make CMOS versions these days. And versions with more lax timing 
requirements. Even more lax than the original part. (Which means 
flexibility) And a whole lot faster. One of the really cool things about 
this chip for embedded micro users is that you can program it to take a 
nibble at a time. If you have a small Atmel processor or something, this 
can be a real help.

You can power a LED directly from the ports on these things so, Rude, if 
you've got a box load of these things, go build yourself a xmas tree or 
something. :)

So I have these old Akai cassette decks. I never throw anything out which 
is probably why it's more cluttered in here than the Mir space station was. 
Err but when I say "I'm making progress", I don't mean, crash a "progress" 
into me. OK. The thing about these Akai cassette decks is that they have 
these really cute bright blue plasma/flouro/something VU meter displays on 
them. I have no idea how they work since the voltages that run them defy 
what I know about these kinds of displays. But anyway, they're driven by 
these mystical HA12019 chips.

One of these decks I'd previously turned into a microphone pre-amp + 
Headphone amp. It has an amazingly quite pair of mic preamps in it but I 
also added a valve preamp one day in a rare moment of clarity. The second 
one, I have just performed one of my more inspired acts of device surgery 
on and have actually managed to cut out an entire section of front panel. 
Complete with VU meter, headphone socket and balance control.

The whole thing, including rear mounting bracket has been surgically 
implanted into the front of my new sequencer box. //ADICT II. It actually 
looked pretty groovy and with it's 19" rack ears on, it looks like no 
computer you've ever seen before.

In order to do this, I had to rip out the cassette deck's PSU as well. This 
is because the VU meter requires 3.2volts AC. This seems horribly low for 
some kind of plasma discharge display so I figure there's something gnarly 
going on inside it's little glass envelope. There's no other components on 
the board other than the 2 VU chips.

So I've got this small linear PSU with a range of really smooth voltages 
available and I'm wondering if it were possible to run the VU meters in 
Bar/dot mode. If so I could build up a small mux and make this thing worth 
drooling over.

Why would anyone in their right mind want to mount half a cassette deck in 
the front of their computer? Hey I never said I was in my right mind. I'm 
just borrowing this one while mine's in the shop for repairs. But it does 
look good and the previous incarnation of this machine had some big ol' VU 
meters mounted in the drive bay so it's a bit of a tradition now.

But anyway, if someone has any information at all about this chip, I'd most 
appreciate it.

Thanks in advance.

Be absolutely Icebox.

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