[dorkbotpdx-blabber] another LED array question

[Mykle Hansen]

On Dec 16, 2008, at 3:32 PMTuesday, David Frech wrote:

> This may be more complex than needed for this application, but it's a
> useful approach in general.

good to know.   probably there would be 8 vertical "modules",
arrayed around a vertical axis.  they could be hooked together
around the top via a ribbon cable.  so i could easily divide
this into 8 banks, using your technique.  but still, i'm not
sure i need to.  even updating every single led on every single
change, it seems i can get thousands of updates per second.
(unless the cascading of chips slows things way, way down ...)

i'm still kind of interested in a 16 or 24-bit
solution because the LEDs are broken into 8 rows of 5, so that's
either 15 channels per column or 24 channels per row.  but i'm just
not sure if working with QFN-size packages will be feasible.
so probably a pair of 8-channel chips on each of 8 columns
is workable.

> BTW, I didn't know about the TI TPIC6C596N chips. They are pretty
> sweet. But I can't tell how the 596 is different from the TPIC6C595N
> (which is obviously modeled on our old friend the HC595). Can anyone
> enlighten me here?

i'm a little confused which chips we're talking about.  there's
the 5947, which is the fancy pants one: 24 channels, 12 bits
of resolution per channel, a thermal protection switch and
constant-current regulation, and i think it also makes lasers
shoot out of your eyes.  that's what i'd like to use, for a
one-off.  unless it's too small, in which case i'd like the
closest thing in a dip package.  and a pony.

then there's a bunch of 16-bit variations, even including ones
with i2c inputs (5943).  and the 8-bit version in DIP format
is the TLC5916.  is that what you mean?

looking at the hc595 sheet, it looks like the pins are just
off/on instead of internal PWM ... of course i could PWM them
manually, now that i think of it.  but i'd rather not have to.

-mykle-
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