Max7219 8-digit display driver

Archiver

I am planning to make a counter incorporating a MAX7219 8-digit
display driver. I have looked at some of the BS2 code and the MAX7219
data sheet. I am getting ready to start. However, I have selected a
1" seven segment common cathode LED (I'll use 8 of these) but I am
not quite sure if i need external drivers for the LEDS or if the
MAX7219 can handle the displays without.

Any suggestions?

Thanks,
Guy

Archiver

Since the MAX7219 is a multiplexer [noparse][[/noparse]only one digit is lit at a time], you
won't have any problems. There is a current limiter in the circuit. You can
always adjust that if you need to for your specific displays.

-- Jon Williams


In a message dated 8/13/02 11:31:49 PM Central Daylight Time,
guyb@m... writes:


> I am planning to make a counter incorporating a MAX7219 8-digit
> display driver. I have looked at some of the BS2 code and the MAX7219
> data sheet. I am getting ready to start. However, I have selected a
> 1" seven segment common cathode LED (I'll use 8 of these) but I am
> not quite sure if i need external drivers for the LEDS or if the
> MAX7219 can handle the displays without.
>
> Any suggestions?
>
> Thanks,
>




[noparse][[/noparse]Non-text portions of this message have been removed]

Archiver

I have not used the MAX7219 before but I interpret the MAX7219 data
sheet and BS2 code examples to process & display only one digit at a
time, but to display multiple digit results as required e.g.
display "1234" and no leading zeros. I think I might be OK on the
device that I selected since the typ forward voltage is 3.4V and the
typ forward current is 10mA.

What are your thoughts?

Guy

--- In basicstamps@y..., jonwms@a... wrote:
> Since the MAX7219 is a multiplexer [noparse][[/noparse]only one digit is lit at a
time], you
> won't have any problems. There is a current limiter in the
circuit. You can
> always adjust that if you need to for your specific displays.
>
> -- Jon Williams
>
>
> In a message dated 8/13/02 11:31:49 PM Central Daylight Time,
> guyb@m... writes:
>
>
> > I am planning to make a counter incorporating a MAX7219 8-digit
> > display driver. I have looked at some of the BS2 code and the
MAX7219
> > data sheet. I am getting ready to start. However, I have selected
a
> > 1" seven segment common cathode LED (I'll use 8 of these) but I
am
> > not quite sure if i need external drivers for the LEDS or if the
> > MAX7219 can handle the displays without.
> >
> > Any suggestions?
> >
> > Thanks,
> >
>
>
>
>
> [noparse][[/noparse]Non-text portions of this message have been removed]