LED displays and MAX7219

Archiver

The MAX7219 is an excellent choice for driving up to 8 digit
displays. LCD's are o.k for many things but LED's can't be beat for
contrast, visability and ruggedness. In my opinion, this driver has
been way under used in stamp applications. In all the books on
stamps, (and I have them all) the MAX7219 is only used 3 times. The
best example is in the Scott Edwards book as a thermometer readout
with the DS1620. I would like to see more projects with the 7219,
especially a 6 digit clock. This clock would get it's reference from
the 60 cycle via an opto-isolator to the Stamp instead of a RTC.
DIGI-KEY has some really kool Blue LED displays from LITEON, P/N 160-
1524-5-ND. They have a Vf of 3.8 volts. I built a really neat 6
digit clock with these displays using a preprogrammed PIC from LNS
Technologies that comes with their CLOCK6 Kit. I am not advanced
enough in my studies to write the code for the clock I described but
it would make a nice article if someone would to it.

Archiver

I sometimes use the MAX7219, but frankly I always try to avoid using
it, because of several reasons.

1. The price of the MAX 7219 is high. One unit could cost 8$, if
you're only baying one at the time.
2. The pcb-layout need careful planning, not to do mistakes. And the
time with this planning and studding the data from Maxim has to be
taken into account. You can't remember the connection from project
to project.
3. Work all day, make a PCB that work, then...only display some
numbers.....No, sorry. I try to use an Alpha-numeric LCD display
serial/parallel. Mutch more info out for etch dollar. Only 2 - 5
connections, and you're up and running the code.

Off cores, sometimes the design needs an 8-segment numeric display.
So then you have to use it.

But keep playing with the MAX7219, the experience is valuable in it
self.

Stein.

--- In basicstamps@yahoogroups.com, "Doug Wood" <douglout@m...>
wrote:
> The MAX7219 is an excellent choice for driving up to 8 digit
> displays. LCD's are o.k for many things but LED's can't be beat
for
> contrast, visability and ruggedness. In my opinion, this driver
has
> been way under used in stamp applications. In all the books on
> stamps, (and I have them all) the MAX7219 is only used 3 times.
The
> best example is in the Scott Edwards book as a thermometer readout
> with the DS1620. I would like to see more projects with the 7219,
> especially a 6 digit clock. This clock would get it's reference
from
> the 60 cycle via an opto-isolator to the Stamp instead of a RTC.
> DIGI-KEY has some really kool Blue LED displays from LITEON, P/N
160-
> 1524-5-ND. They have a Vf of 3.8 volts. I built a really neat 6
> digit clock with these displays using a preprogrammed PIC from LNS
> Technologies that comes with their CLOCK6 Kit. I am not advanced
> enough in my studies to write the code for the clock I described
but
> it would make a nice article if someone would to it.

Archiver

All right then, Doug, write a good app note for us to post! We've
certainly provided ample information to assist BASIC Stamp users with
the MAX7219.

-- Jon Williams
-- Applications Engineer, Parallax
-- Dallas Office

---

Original Message

---

From: Doug Wood [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=hl1DnrG-FBZh98CxciIttkCHtLW8YNwjlifbqjYFanWmm39FX4D3ZKI2xMcnFlv51DXGsM5IlDs]douglout@m...[/url
Sent: Saturday, April 17, 2004 12:21 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] LED displays and MAX7219


The MAX7219 is an excellent choice for driving up to 8 digit
displays. LCD's are o.k for many things but LED's can't be beat for
contrast, visability and ruggedness. In my opinion, this driver has
been way under used in stamp applications. In all the books on
stamps, (and I have them all) the MAX7219 is only used 3 times. The
best example is in the Scott Edwards book as a thermometer readout
with the DS1620. I would like to see more projects with the 7219,
especially a 6 digit clock. This clock would get it's reference from
the 60 cycle via an opto-isolator to the Stamp instead of a RTC.
DIGI-KEY has some really kool Blue LED displays from LITEON, P/N 160-
1524-5-ND. They have a Vf of 3.8 volts. I built a really neat 6
digit clock with these displays using a preprogrammed PIC from LNS
Technologies that comes with their CLOCK6 Kit. I am not advanced
enough in my studies to write the code for the clock I described but
it would make a nice article if someone would to it.

Archiver

Doug,

I have been wanting to do a clock! Please contact me at
FrankSmith512@y....

Thanks,
Frank



--- In basicstamps@yahoogroups.com, "Doug Wood" <douglout@m...> wrote:
> The MAX7219 is an excellent choice for driving up to 8 digit
> displays. LCD's are o.k for many things but LED's can't be beat for
> contrast, visability and ruggedness. In my opinion, this driver
has
> been way under used in stamp applications. In all the books on
> stamps, (and I have them all) the MAX7219 is only used 3 times.
The
> best example is in the Scott Edwards book as a thermometer readout
> with the DS1620. I would like to see more projects with the 7219,
> especially a 6 digit clock. This clock would get it's reference
from
> the 60 cycle via an opto-isolator to the Stamp instead of a RTC.
> DIGI-KEY has some really kool Blue LED displays from LITEON, P/N
160-
> 1524-5-ND. They have a Vf of 3.8 volts. I built a really neat 6
> digit clock with these displays using a preprogrammed PIC from LNS
> Technologies that comes with their CLOCK6 Kit. I am not advanced
> enough in my studies to write the code for the clock I described
but
> it would make a nice article if someone would to it.