8 x 8 LED Dotmatrix - MAX 7219
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Hi
Has anyone used the MAX7219 in Dotmatrix mode ie 8 x 8 LED array?
I'm wondering if anyone has written or know where I can find the
following:-
A scrolling routine Left/right/Up/Down
A Charactor displaying routine
A Sprite displaying routine
I have managed the above but would like to see if anyone can improve
on speed and "tricks" using clever maths.
My display is 7 max's cascaded together = 448 LEDs
Any help would be apprecitated.
Thanks
Chris
Has anyone used the MAX7219 in Dotmatrix mode ie 8 x 8 LED array?
I'm wondering if anyone has written or know where I can find the
following:-
A scrolling routine Left/right/Up/Down
A Charactor displaying routine
A Sprite displaying routine
I have managed the above but would like to see if anyone can improve
on speed and "tricks" using clever maths.
My display is 7 max's cascaded together = 448 LEDs
Any help would be apprecitated.
Thanks
Chris
Comments
Has no one ever used the Max 7219 as a 8x8 array, I'm I the only one ?
Cheers
Chris
--- In basicstamps@egroups.com, "Chris Hill" <Christopher_Hill@M...>
wrote:
> Hi
>
> Has anyone used the MAX7219 in Dotmatrix mode ie 8 x 8 LED array?
>
> I'm wondering if anyone has written or know where I can find the
> following:-
>
> A scrolling routine Left/right/Up/Down
> A Charactor displaying routine
> A Sprite displaying routine
>
> I have managed the above but would like to see if anyone can
improve
> on speed and "tricks" using clever maths.
>
> My display is 7 max's cascaded together = 448 LEDs
>
> Any help would be apprecitated.
>
> Thanks
> Chris
I've used it. The LEDs (60 of them) were wired in an 8x8 array, but not
physically arranged that way. I only had a single 7219, but the prospectes
of more than one sounds fun. I don't have any real tricks to
recommendations. The only thing that has burned me (more than once, I might
add) is to make sure you implement the current limiting resistor on the
7219. If you don't, your LEDs may not light. The other thing is to watch
your power. I used a 20 ohm resistor across the current limiting pin, but
with all 60 LEDs lit, the circuit still draws nearly 800mA (at 5V) (that
includes a MAX232-A, and a Scenix SX18 running 50 Mhz). Most of the current
is going through the 7219, though. Without the LEDs lit, the circuit only
draws like 100mA.
-- Mitch
Original Message
From: Chris Hill [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=zyD2AXkOrX_TmNI68spalm_Txu0Yo2wtD3my_BPLKAu8Qf5UUy_x68uuzrBeE_x-T6Cf0gaKUBPTtNOM0dHWLT21PA]Christopher_Hill@M...[/url
Sent: Monday, December 11, 2000 9:58 AM
To: basicstamps@egroups.com
Subject: [noparse][[/noparse]basicstamps] Re: 8 x 8 LED Dotmatrix - MAX 7219
Hi Again
Has no one ever used the Max 7219 as a 8x8 array, I'm I the only one ?
Cheers
Chris
--- In basicstamps@egroups.com, "Chris Hill" <Christopher_Hill@M...>
wrote:
> Hi
>
> Has anyone used the MAX7219 in Dotmatrix mode ie 8 x 8 LED array?
>
> I'm wondering if anyone has written or know where I can find the
> following:-
>
> A scrolling routine Left/right/Up/Down
> A Charactor displaying routine
> A Sprite displaying routine
>
> I have managed the above but would like to see if anyone can
improve
> on speed and "tricks" using clever maths.
>
> My display is 7 max's cascaded together = 448 LEDs
>
> Any help would be apprecitated.
>
> Thanks
> Chris
I have built a simple 6 character scrolling message display using
UCN5810 shift registers and 6 7x5 dot matrix LED blocks (total
resolution is 30 x 7). I found that as I added more animations or
more characters, the display began to flicker, suggesting that the
BS2 is not fast enough to keep up with the display refresh
requirements. Did you have this type of problem? If not, I'd be very
interested in seeing your circuit and program, and I'd be willing to
try to improve it if possible.
Regards,
Grahame
--- In basicstamps@egroups.com, "Chris Hill" <Christopher_Hill@M...>
wrote:
> Hi Again
>
> Has no one ever used the Max 7219 as a 8x8 array, I'm I the only
one ?
>
> Cheers
> Chris
>
>
> --- In basicstamps@egroups.com, "Chris Hill"
<Christopher_Hill@M...>
> wrote:
> > Hi
> >
> > Has anyone used the MAX7219 in Dotmatrix mode ie 8 x 8 LED array?
> >
> > I'm wondering if anyone has written or know where I can find the
> > following:-
> >
> > A scrolling routine Left/right/Up/Down
> > A Charactor displaying routine
> > A Sprite displaying routine
> >
> > I have managed the above but would like to see if anyone can
> improve
> > on speed and "tricks" using clever maths.
> >
> > My display is 7 max's cascaded together = 448 LEDs
> >
> > Any help would be apprecitated.
> >
> > Thanks
> > Chris
I have built a simple 6 character scrolling message display using
UCN5810 shift registers and 6 7x5 dot matrix LED blocks (total
resolution is 30 x 7). I found that as I added more animations or
more characters, the display began to flicker, suggesting that the
BS2 is not fast enough to keep up with the display refresh
requirements. Did you have this type of problem? If not, I'd be very
interested in seeing your circuit and program, and I'd be willing to
try to improve it if possible.
Regards,
Grahame
--- In basicstamps@egroups.com, "Chris Hill" <Christopher_Hill@M...>
wrote:
> Hi Again
>
> Has no one ever used the Max 7219 as a 8x8 array, I'm I the only
one ?
>
> Cheers
> Chris
>
>
> --- In basicstamps@egroups.com, "Chris Hill"
<Christopher_Hill@M...>
> wrote:
> > Hi
> >
> > Has anyone used the MAX7219 in Dotmatrix mode ie 8 x 8 LED array?
> >
> > I'm wondering if anyone has written or know where I can find the
> > following:-
> >
> > A scrolling routine Left/right/Up/Down
> > A Charactor displaying routine
> > A Sprite displaying routine
> >
> > I have managed the above but would like to see if anyone can
> improve
> > on speed and "tricks" using clever maths.
> >
> > My display is 7 max's cascaded together = 448 LEDs
> >
> > Any help would be apprecitated.
> >
> > Thanks
> > Chris
There seem to be an interest in LED Displays within the group but no
real pointers in the goal of a Large LED Display. If I get time I'm
thinking of throwing a WEB site together listing my LED projects for
others to comment on and share.
I've currently used the MAX thinking It will reduce chip count/cost.
I've been driving them with a BS2sx. This I think is my problem when
it comes to Scrolling, getting enough speed out of the BS to reduce
flicker. I've never had the time to move to assembler or another
processor. However just to let you know what I've managed to do so
far with a BS2sx are:-
A 16 Charactor Star burst LED Display - (64 LEDs /charactor - 250mm
heigh)
A 28 Charactor Display - (256 LEDs / 64 dots ( 8x8 array)/ Charactor -
244 mm x 244mm) - Total size 1745mm x 1015mm - 7168 LEDs in total -
draws only about 8 amps in total.
These all work perfectly well the only draw back is Speed when
scrolling.
I've also done some 7 Seg digits 400mm height
If the group is interested I'll post this on a WEBsite in the new
year, please let me know ?
Cheers Chris
--- In basicstamps@egroups.com, "Mitchell D. Miller" <mdmiller2@h...>
wrote:
> Chris,
>
> I've used it. The LEDs (60 of them) were wired in an 8x8 array,
but not
> physically arranged that way. I only had a single 7219, but the
prospectes
> of more than one sounds fun. I don't have any real tricks to
> recommendations. The only thing that has burned me (more than
once, I might
> add) is to make sure you implement the current limiting resistor on
the
> 7219. If you don't, your LEDs may not light. The other thing is
to watch
> your power. I used a 20 ohm resistor across the current limiting
pin, but
> with all 60 LEDs lit, the circuit still draws nearly 800mA (at 5V)
(that
> includes a MAX232-A, and a Scenix SX18 running 50 Mhz). Most of
the current
> is going through the 7219, though. Without the LEDs lit, the
circuit only
> draws like 100mA.
>
> -- Mitch
>
>
Original Message
> From: Chris Hill [noparse][[/noparse]mailto:Christopher_Hill@M...]
> Sent: Monday, December 11, 2000 9:58 AM
> To: basicstamps@egroups.com
> Subject: [noparse][[/noparse]basicstamps] Re: 8 x 8 LED Dotmatrix - MAX 7219
>
>
> Hi Again
>
> Has no one ever used the Max 7219 as a 8x8 array, I'm I the only
one ?
>
> Cheers
> Chris
>
>
> --- In basicstamps@egroups.com, "Chris Hill" <Christopher_Hill@M...>
> wrote:
> > Hi
> >
> > Has anyone used the MAX7219 in Dotmatrix mode ie 8 x 8 LED array?
> >
> > I'm wondering if anyone has written or know where I can find the
> > following:-
> >
> > A scrolling routine Left/right/Up/Down
> > A Charactor displaying routine
> > A Sprite displaying routine
> >
> > I have managed the above but would like to see if anyone can
> improve
> > on speed and "tricks" using clever maths.
> >
> > My display is 7 max's cascaded together = 448 LEDs
> >
> > Any help would be apprecitated.
> >
> > Thanks
> > Chris
I'm running out of time today, but 2 things I've just replyed to
Mitch with a bit more stuff and secondly yes your right a Shift
register may be an option to go down for speed.
However I'll post a relavent part of my code for your interest.
Please if you can improve on it let me know. (If it needs more
comments on the code let me know and I'll do it later.)
Cheers Chris
Code for BS2sx driving 7 Max7219 in cascade.
This is only part of the program as I think it is two big to post on
the group pages.
'*********************************************************************
*******************
'Global Display of 1 Row TEXT - Note reverse of Data Array - Tuned
for Speed - WATCHOUT FOR HARD CODING
'*********************************************************************
*******************
Global_Display:
Dot_Offset=0 'Start point of scrolling
Msg_Position = 1 'Four rows of Seven Max's
Start_Row:
Message_Offset = (Dot_Offset/8)
Message_Offset_1 = 1
Next_Row:
For Mod_Dig = 1 to 8 'Columns of display
Digit_Offset = (((Mod_Dig-1) - (Dot_Offset//8)) //8 + 1) 'This bit
decides what charactor to get from the message and where to start
If Digit_Offset > Mod_Dig Then Next_Char
Message_Offset_1 = 0
Next_Char:
For N = 0 to NUM_Of_Modules - 1 'Load all Modules at once
with each Column Data
Read Text_Message_Data + N + Message_Offset + Message_Offset_1,
Char_Pointer 'Read Text Message charator
Read_Char_Data:
Read ((Char_Pointer-32) * 8 + Char_Map_Data) + Digit_Offset,
Mod_Data_A(N) 'Read Text Message data
Next 'Next Modules Column Data
Shiftout Row_Data(Msg_Position),Row_Clk
(Msg_Position),msbfirst,[noparse][[/noparse]Mod_Dig,Mod_Data_A(0),Mod_Dig,Mod_Data_A
(1),Mod_Dig,Mod_Data_A(2),Mod_Dig,Mod_Data_A(3),Mod_Dig,Mod_Data_A
(4),Mod_Dig,Mod_Data_A(5),Mod_Dig,Mod_Data_A(6)]
PulsOut Row_Load(Msg_Position),5
Next 'Get Next Set of Column Data
If Dot_Offset > 255 then End_Message 'scroll message by 1 dot
Dot_Offset = Dot_Offset +1
Goto Start_Row
End_Message:
Return
'Message and text data
Text_Message_Data Data "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ
SPACE " 'Test Charactor Set
'Data blocks from 32 upwards only shown 48 / 49 for example - 8 x 8
charactor definitions
Char_Map_Data Data (1) 'Dummy Offset
1
Data %01111110 '"0" space
ASCII Code 48
Data %10000001
Data %10000001
Data %10000001
Data %10000001
Data %10000001
Data %10000001
Data %01111110
Data %00000000 '"1" space
ASCII Code 49
Data %00000000
Data %00000000
Data %00000001
Data %11111111
Data %01000001
Data %00000000
Data %00000000
--- In basicstamps@egroups.com, sisinfo@s... wrote:
> Chris,
>
> I have built a simple 6 character scrolling message display using
> UCN5810 shift registers and 6 7x5 dot matrix LED blocks (total
> resolution is 30 x 7). I found that as I added more animations or
> more characters, the display began to flicker, suggesting that the
> BS2 is not fast enough to keep up with the display refresh
> requirements. Did you have this type of problem? If not, I'd be
very
> interested in seeing your circuit and program, and I'd be willing
to
> try to improve it if possible.
>
> Regards,
> Grahame
>
>
> --- In basicstamps@egroups.com, "Chris Hill"
<Christopher_Hill@M...>
> wrote:
> > Hi Again
> >
> > Has no one ever used the Max 7219 as a 8x8 array, I'm I the only
> one ?
> >
> > Cheers
> > Chris
> >
> >
> > --- In basicstamps@egroups.com, "Chris Hill"
> <Christopher_Hill@M...>
> > wrote:
> > > Hi
> > >
> > > Has anyone used the MAX7219 in Dotmatrix mode ie 8 x 8 LED
array?
> > >
> > > I'm wondering if anyone has written or know where I can find
the
> > > following:-
> > >
> > > A scrolling routine Left/right/Up/Down
> > > A Charactor displaying routine
> > > A Sprite displaying routine
> > >
> > > I have managed the above but would like to see if anyone can
> > improve
> > > on speed and "tricks" using clever maths.
> > >
> > > My display is 7 max's cascaded together = 448 LEDs
> > >
> > > Any help would be apprecitated.
> > >
> > > Thanks
> > > Chris
Hi Chris and others -
Just a quick comment about processor speed for LED and other projects. You
will
be quite happy to see the performance and speed of the NEW BS2-P (aka
BS2-SX +).
The Parallax web site now has the NEW manual for download. The FIRST PAGE of
the website tells you ALL ABOUT it.
[noparse][[/noparse] http://www.parallaxinc.com/ ] What's New Section (where else : )
Regards,
Bruce Bates
P.S. If anyone has difficulty accessing the web server (as happened yesterday)
an alternate FTP method has been provided:
ftp://ftp.parallaxinc.com
Login using the name "stamper" with a password of "manual".
(per Ken Gracey)