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Sadaf
Joined: 07 Feb 2003
Posts: 10
Location: Lahore, Pakistan
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 09 Oct 2003 12:13 DIY Moving Message Display |
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Hi all
I want to have moving message display program for atmel AT89C251. May some one help me?
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Epegic
Joined: 29 Mar 2002
Posts: 89
Helped: 3
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| 10 Oct 2003 4:49 Re: Software for Moving Message Display |
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| Embedded control software always depends on hardware design. It is hopeless to any advice if you don't mention clearly what you wanted.
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Sadaf
Joined: 07 Feb 2003
Posts: 10
Location: Lahore, Pakistan
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| 10 Oct 2003 16:35 Re: Software for Moving Message Display |
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| Epegic wrote: |
| Embedded control software always depends on hardware design. It is hopeless to any advice if you don't mention clearly what you wanted. |
Thanks for reply.... suppose I have a text string like "Well Come We have all stuf you want". I want to get it scrool over and over... moving letters on a 7x9 led matrix. I saw a unit which was doing this. In that unit it was possible that you change the moving message with the help of a infra red remote control. It means that moving message has built in characterset.. from which letters can be selected to make a message. It contains 19 led matrix displays (7 x 9). May it help to advice me ATMEL based Hardware design and its software? Thanks again.
Saif
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Epegic
Joined: 29 Mar 2002
Posts: 89
Helped: 3
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| 13 Oct 2003 5:05 Re: Software for Moving Message Display |
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| It doesn't help too much. The first thing to do is design driving hardware for LED matrix. Software is used to pump display data and control how data are displayed. Simple hardware need complicate software and vice vera.
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senthilkumar
Joined: 24 Nov 2001
Posts: 617
Helped: 3
Location: india
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| 13 Oct 2003 6:01 |
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hai,
u go and search maxim ic for led matrix display.
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Al Farouk
Joined: 13 Jan 2003
Posts: 194
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| 14 Oct 2003 10:51 Re: Software for Moving Message Display |
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Dear saif
I think that I understand what you need. The idea os the design of the moving message as follows
The shape of the characters are saved in EPROM (for example) and the display matrix are arranged in row and columns each column can be enabled individually.
Counters are used to address the contents of the EPROM in synchrounous with the columns enabled sequence so the shape of the character can be drwan on the Matrix.
to show the moving effect, enable column n then n-1 then n-2 and display the output of the EPROM content on the appropreiat column, repeat this action for example 25 --> 50 time/second.
repeat the last setp by shifting the columns address i.e enable n+1 then n then n-1 and so on.
repeat the last step till the end of your dislay matrix, you get the moving effect.
regards
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Sadaf
Joined: 07 Feb 2003
Posts: 10
Location: Lahore, Pakistan
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| 15 Oct 2003 12:57 Re: Software for Moving Message Display |
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Dear Al Farouk
Thank you verymuch for your reply... You are very right ... you got it.... now I am posting pcb design and parts layout of a portion of actual unit as suggested Mr. Epegic in his pm. May it help to advice me more on this topic.
Thanks
Saif
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Al Farouk
Joined: 13 Jan 2003
Posts: 194
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| 15 Oct 2003 16:03 Re: Software for Moving Message Display |
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Dear Saif
My advice to you is
you should first reverse engineer the board you have to get sch first and then study the idea behind the sch to be able to understand the correct layout and the track width in each section.
this also will help you to writ down the program that will be run by the microcontroller.
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ME
Joined: 14 Mar 2002
Posts: 1771
Helped: 11
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| 15 Oct 2003 16:19 |
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This link may be very useful:
http://home.wanadoo.nl/electro1/avr/dotmatrix.htm
It uses an Atmel AVR AT90S2313 for controlling eight 5x7 LED dotmatrix displays.
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GrandAlf
Joined: 09 Mar 2002
Posts: 249
Helped: 8
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| 15 Oct 2003 16:30 Re: Software for Moving Message Display |
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| Normally these units have a serial i/p for computer programming with a fairly simple protocol. Are you sure that the one you are looking at does not have this facilty?, if not there are plenty that do.
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ME
Joined: 14 Mar 2002
Posts: 1771
Helped: 11
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| 15 Oct 2003 16:41 Re: Software for Moving Message Display |
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| GrandAlf wrote: |
| Normally these units have a serial i/p for computer programming with a fairly simple protocol. Are you sure that the one you are looking at does not have this facilty?, if not there are plenty that do. |
The one that I linked to have RS232 interface for connetion to PC:
http://home.wanadoo.nl/electro1/avr/scroll6.htm
But I doesnt seems like the one posted by Saif have any connector except a Powersupply plug.
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Tornado
Joined: 26 Apr 2002
Posts: 340
Helped: 1
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Epegic
Joined: 29 Mar 2002
Posts: 89
Helped: 3
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| 16 Oct 2003 5:10 Re: Software for Moving Message Display |
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Saif,
Is this your own design?
PCB layout is not so good for understand the circuit, schematic diagram will be much better.
Some advices:
I don't have detail specification of 164 and 7445, 164 have to provide 5~20mA, depends on LED used. 7445 need 5 times the driving current.
Refresh rate should be >40Hz(very flicker) to 70Hz(very stable), that means switching each row in (1/40/7) 3.5ms to (1/70/7) 2ms, setup a timer to involve the scan() function.
A prelimary algorithm for your reference
Assuming Port1 connected to 7445 and port 2 to 164,
4 bytes (25 columns) used for display data for each row.
dispBuffer[row][col/8];
#define Sclock P^0;
#define Sdata P^1;
void scan(void) {
for (row=0; row<7 row++) {
P1 = 0x00; // turn off display
for (i=0; i<4; i++) // send 4 bytes of display data
outOneByte(dispBuffer[row][i]); // send data to 164
P1 = 0x01<<row; // enable one single row
} }
void outOneByte(dispData) {
Sclock = 0; // serial clock low
for (i=0; i<8; i++) { //send 8 bits
if ((dispData & 0x01)==1) Sdata = 1;
else Sdata =0;
Sclock =1;
dispData >>=1;
} }
The above code fragments are by no means accurate, by only give a rough idea, you have to rewrite to fit your suituation
I will search some reference designs for you later.
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Al Farouk
Joined: 13 Jan 2003
Posts: 194
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| 16 Oct 2003 8:34 Re: Software for Moving Message Display |
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| The circuit supplied by ME also need a storage media (EPROM, EEPROM, or else) to be read at poer up and also facilitate the field updating.
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ME
Joined: 14 Mar 2002
Posts: 1771
Helped: 11
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| 16 Oct 2003 9:52 Re: Software for Moving Message Display |
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| Al Farouk wrote: |
| The circuit supplied by ME also need a storage media (EPROM, EEPROM, or else) to be read at poer up and also facilitate the field updating. |
You can download the program with the ISP connector, then you can program the text inide the Flash memory as a part of the program, then you don't need any eeprom. If there is not enough space in the AVR, then you can just use a bigger AVR with more Flash memory.
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tobb
Joined: 20 Sep 2002
Posts: 87
Helped: 1
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| 16 Oct 2003 10:03 |
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HI .. The circuit supply by ME is good one . it use internal eeprom to store upto 128 char for moving message. I'm currently work on 16*32 led moving bar. it use sanyo LC7932 16 bit shift open drain ic.
i use timer interupt for shift every column and i use internal eeprom to store letter the logic will like this
read column(i)
send shift data to ic controll column
display column(i)
increase i
this will display static data so i need to chage column data to make it move in a time that i set .. I try this and it work.. but my source code is writen in bascom and it use with LC7932 Driver + AT90S2313 .. if anyone interest i could post it here..
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ME
Joined: 14 Mar 2002
Posts: 1771
Helped: 11
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| 16 Oct 2003 10:10 |
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| tobb wrote: |
HI .. The circuit supply by ME is good one . it use internal eeprom to store upto 128 char for moving message. I'm currently work on 16*32 led moving bar. it use sanyo LC7932 16 bit shift open drain ic.
i use timer interupt for shift every column and i use internal eeprom to store letter the logic will like this
read column(i)
send shift data to ic controll column
display column(i)
increase i
this will display static data so i need to chage column data to make it move in a time that i set .. I try this and it work.. but my source code is writen in bascom and it use with LC7932 Driver + AT90S2313 .. if anyone interest i could post it here.. |
I just looked at the site I linked to and I can't find the sourcecode or hex file, have you found the source code or hex at the site?
Just upload the bascom code, it's a small file, I'm sure it will be usefull to someone, eventhough I don't use Basic.
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Sadaf
Joined: 07 Feb 2003
Posts: 10
Location: Lahore, Pakistan
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| 17 Oct 2003 12:11 |
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Thanks all...
I am grateful all of you... It helped me very much to understand the program logic for moving message display. If readymade program code is available anywere than please tell. I am also trying to write one... If I succeeded ... I will place one on this forum for others to use it in their project.
Thanks again
Saif
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neuralc
Joined: 06 Nov 2001
Posts: 270
Helped: 5
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| 17 Oct 2003 13:26 |
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Hi,
Let me place a question about hardware.
Do you have already tried to switch ON all the leds (or 80% of them)?
NeuralC
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tobb
Joined: 20 Sep 2002
Posts: 87
Helped: 1
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| 18 Oct 2003 7:33 Re: Software for Moving Message Display |
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For this Question
| Quote: |
Let me place a question about hardware.
Do you have already tried to switch ON all the leds (or 80% of them)?
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Yes.. If from my hardware. I have try enable all 512 leds and it all work find. the only ploblem is if you scan leds to slow it could be easily see it flickers. The led maxtrix use scan methode so the power supply can be smaller and for me i use only one 7805 to feed my micro and 512 leds
And this is a simple code that move image display to right and also with my system picture
Here is Bascom code,
Dim Outser1 As Integer
Dim Outser2 As Integer
Dim Outprt As Byte
Dim Outrow As Integer
Dim Outserlong As Long
Dim Tmplong As Long
Dim Sr_cnt As Byte
Dim Sr_cnt_zero As Byte
Dim Sr_cnt_first As Byte
Dim Sr_cnt_second As Byte
Dim Page As Byte
Dim En_flage As Byte
Dim I As Byte , J As Byte , K As Byte
Dim I_zero As Byte
Dim I_invert As Byte
Dim Shifttime As Integer
Dim Shiften As Byte
$eeprom
Data &B0000000000000000%
Data &B0000000000000000%
Data &B0101010011100000%
Data &B0101010100010000%
Data &B0101010111110000%
Data &B0101010100000000%
Data &B0010100011100000%
Data &B0000000000000000%
Data &B0000000000000000%
Data &B0111001000000100%
Data &B0100100001100001%
Data &B0100101010010100%
Data &B0100101010010100%
Data &B0111001001110100%
Data &B0000000000010000%
Data &B0000000001100000%
Data &B0000000000001010%
Data &B0110001100000101%
Data &B1001010010000010%
Data &B1000100010110001%
Data &B1000000011001000%
Data &B0100000100001000%
Data &B0010001100010000%
Data &B0001010010100000%
Data &B0000100001000000%
Data &B1000000010001010%
Data &B1100110010001010%
Data &B1001001010001010%
Data &B1001001010001010%
Data &B1000111010000000%
Data &B0000000000001010%
Data &B0000000000000000%
Config Portb = Output
Config Timer0 = Timer , Prescale = 8
Enable Timer0
Enable Interrupts
On Ovf0 Tim0_isr
Do
Loop
Tim0_isr:
Disable Interrupts
Incr Shifttime
If Shifttime = 150 Then
Incr Shiften
If Shiften = 32 Then Shiften = 0
Shifttime = 0
End If
Sr_cnt_zero = Sr_cnt - 1
Sr_cnt_first = Sr_cnt_zero * 2
Sr_cnt_second = Sr_cnt_zero + 16
Sr_cnt_second = Sr_cnt_second * 2
Readeeprom Outser1 , Sr_cnt_first
Readeeprom Outser2 , Sr_cnt_second
For I = 0 To 31
J = I - 16
If I < 16 Then Outserlong.i = Outser1.i
If I >= 16 Then Outserlong.i = Outser2.j
Next I
Tmplong = Outserlong
If Shiften > 0 Then
Shift Outserlong , Left , Shiften
For I = 0 To Shiften
K = Shiften - I
J = 32 - K
Outserlong.i = Tmplong.j
Next I
End If
For I = 0 To 31
J = I - 16
If I < 16 Then Outser1.i = Outserlong.i
If I >= 16 Then Outser2.j = Outserlong.i
Next I
Set Portb.5
Outrow = &B0000000000000000
Outrow.sr_cnt_zero = 1
For I = 1 To 16
I_zero = I - 1
I_invert = 15 - I_zero
Reset Portb.4
Portb.2 = Outser1.i_invert
Portb.1 = Outser2.i_invert
Portb.0 = Outrow.i_invert
Reset Portb.3
Set Portb.3
Next I
Set Portb.4
Reset Portb.5
If Sr_cnt => 16 Then Sr_cnt = 0
Incr Sr_cnt
Disable Interrupts
Return
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Sadaf
Joined: 07 Feb 2003
Posts: 10
Location: Lahore, Pakistan
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| 18 Oct 2003 12:08 Re: Software for Moving Message Display |
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Thanks tobb
It is great... and thanks also for a part of software... Will you please let me have the hardware of your design... I want to study it also.
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Fragrance
Joined: 26 Jul 2002
Posts: 1312
Helped: 23
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| 18 Oct 2003 13:22 Re: Software for Moving Message Display |
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hi friend
you have to look at the mcs web page to get the code and idea how to design your own instead to reqeusting some one to write down code for you such deficult task
http://www.mcselec.com/an_128.htm
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Sadaf
Joined: 07 Feb 2003
Posts: 10
Location: Lahore, Pakistan
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| 18 Oct 2003 15:38 Re: Software for Moving Message Display |
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Dear Fragrance
Thanks for advice...
I have visited the site ... it is a good for me..
If some one have already done this task he may help me... I can use his software for studying mime... is not it good?
Waiting for your comments.
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ME
Joined: 14 Mar 2002
Posts: 1771
Helped: 11
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| 28 Oct 2003 2:54 |
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Look in the newest issue of the Elektor Electronics magazine (November 2003):
http://www.elektor-electronics.co.uk/ln/details/e1103u.htm
There's an article about a Running Text Display using an 89S8252 Flash MCU.
PCB layout and source & hex code can be downloaded here:
http://www.elektor-electronics.co.uk/dl/details/dl1103.htm
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ME
Joined: 14 Mar 2002
Posts: 1771
Helped: 11
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| 28 Oct 2003 22:39 |
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LED moving font using Atmel AT89C51 or AT89C2051 MCU:
http://www.woe.onlinehome.de/e_projects.htm#ledfont
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bimbla
Joined: 13 Jul 2001
Posts: 536
Helped: 13
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| 29 Oct 2003 2:31 Re: Software for Moving Message Display |
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Is there a circuit based on the PIC controller also?
bimbla.
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tekton
Joined: 12 Sep 2002
Posts: 26
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| 29 Oct 2003 2:37 Re: Software for Moving Message Display |
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hi friends
I need to build an floor indicator with two 5x7 moving number
but with pic 16f84
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ME
Joined: 14 Mar 2002
Posts: 1771
Helped: 11
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| 29 Oct 2003 12:40 Re: Software for Moving Message Display |
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| tekton wrote: |
hi friends
I need to build an floor indicator with two 5x7 moving number
but with pic 16f84 |
Why use the PIC16F84?
It's obsolete and way too expensive.
If you want to use PIC you should chosse the 16F627(A), 16F628(A) or 16F648A.
They are pin compatible replacements for 16F84(A), but much cheaper and with more features. 16F628(A) has 2 times as much flash and PIC16F648A has 4 times as much flash, but is still much cheaper than 16F84(A).
Please read this topic:
http://www.elektroda.pl/eboard/searchtopic43570-16f84.html+16f627+16f628
Prices for 18 pin PDIP, 1-25 units at http://buy.microchip.com:
PIC16F84A-04/P (4 MHz): $5.05 (1024 words FLASH)
PIC16F84A-20I/P (20 Mhz): $5.94
PIC16F84A-20E/P (20 MHz): $6.50
PIC16F84A-20/P (20 MHz): $5.39
PIC16LF627A-I/P (20 MHz): $2.25 (1024 words FLASH)
PIC16F627A-E/P (20 MHz): $2.31
PIC16LF628A-I/P (20 MHz): $2.56 (2048 words FLASH)
PIC16F628A-E/P (20 MHz): $2.60
PIC16LF648A-I/P (20 MHz): $2.93 (4096 words FLASH)
PIC16F648A-I/P (20 MHz): $2.76
PIC16F648A-E/P (20 MHz): $2.97
If you want to use AVR instead, you could use AT90S2313, or the new cheaper, better and faster ATtiny2313, but ATtiny2313 is only availible as samples yet.
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Fragrance
Joined: 26 Jul 2002
Posts: 1312
Helped: 23
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| 01 Jan 2004 12:44 building your own moving message complete guide |
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hi
Here is the complete guide to building your own moving message display
using micro controller
This is a 89C2051 micro-controller project based and 7x16 LED matrix.
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rojo
Joined: 03 Jan 2004
Posts: 17
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| 03 Jan 2004 3:25 Re: building your own moving message complete guide |
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hello
just wondering if u dudes would be interested,
i built my own moving message display with following characteristics:
7x5 led matrix (only four characters at the moment, can be easily extended to any number of characters) connected to an at90s8535
in system programmable controller (very simple programmer), can display around 300 character long messages (depends on the available RAM in the chip) , the controller is connected to a PC keyboard directly,
so the message is typed in and displayed on an LCD (2x16 chars at the moment- also easily upgradable), with next version of software there will be an option for saving message in the
onboard EEPROM (512 bytes), the code is written all in C , compiled with CodeVision C compiler, I only used
their delay() library function so the code is easily portable to other
compilers.compiled code takes around 800 bytes + few hundred bytes
for the font and keyboard scancodes,
(the chip has got 4 K rom & 512 bytes of RAM), currently im working on
getting it to work under a small non-preemptive real time operating system. (also written in C).
here are few pictures of it, let me know if youre interested, thanks  )
Last edited by rojo on 03 Jan 2004 13:17; edited 3 times in total |
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