Moving message on LED dot matrix

[sougata]

Hi,

I have done a moving display with PBP but cannot share it due to commercial restrictions. If you are using Shift Registers then the idea is :

1. Get the font data from a lookup table
2. Dump column data for every row and light up that row, do it in even periods and you have got the scanning.

3. For moving message use a pointer in your message table and update it at regular intervals to scroll.

I know that this is very rudimentary. Post your schematic and I will try to help. I got the lookup table for the 5x7 matrix from this forum by dave and thankful for the same. So perhaps its my turn.

[chai98a]

Hi sougata
Here is picture of circuit 512 ...
There are 8 pin for control

Strobe = control On/Off Dot matrix led display, logic "0" active led on
Latch = control data transfer logic "0"
Clock = clock
Sin1 = control row0,row1
Sin2 = control culum2 , culum3
Sin3 = control culum0 , culum1
Vcc_led = power +5 v
Vcc_IC = power +5 v

[isaac]

From your post i can see that you have a 16 row by 32 Cols
the easy way i would have dont this is use PortB & Portc for for Rows
Then use 4 74hc595 shift reisters for your cols to give you 32bits then use the shiftout command.
Here is an example of an 8 Row by 16 Cols
i used portb for the Rows and 2 74hc595 for the cols
This should get you started

' Program USING 74HC595 .BAS

INCLUDE "Modedefs.bas"
ADCON1=7
TRISA=0:TRISB=0:TRISC=0

'PORT ASSIGNS******************************************* ***
DataP VAR PORTC.0'Data pin (74x595.14)
Clk VAR PORTC.1'shift clock (74x595.11)
Latch VAR PORTC.2'Output Latch(74x595.12)
RowVAR BYTE

'Variables ***********************************************
Delay CON 0'Delay
pattern VAR WORD 'Output pattern
A VAR BYTE ' Loop counter for 16 values of Rows



Pause 1000
Low Latch

main :
pattern = %0000000000000001 'pattern for my columns
For A=0 To 15 ' set the Count 16 times
LookUp A,[0,255,255,24,24,255,255,0,0,255,255,219,219,195,19 5,0],Row
'Those values in the Table should give HE on your display
ShiftOut DataP,Clk,msbFirst,[pattern\16] 'Send pattern to 74x595
PORTB=0 'Blank portb before changing
column
PulsOut Latch,1 'Latch 74x595 outputs
PORTB=Row 'Transfer values from table to
portb
Pause Delay 'Delay
pattern=pattern <<1 'shift pattern 1 place the to left
Next A 'this should give me 0000000000000001 to 1000000000000000


GoTo main






Isaac

[chai98a]

How to set like becode with PBP....

Now we used lookup but we cannot specify line or font number

char const font[3][16] =
{
{0x00,0x00,0x00,0x00,0x00,0x7C,0x40,0x40,0x78,0x40 ,0x40,0x7C,0x00,0x00,0x00,0x00}, //E
{0x00,0x00,0x00,0x00,0x00,0x7C,0x10,0x10,0x10,0x10 ,0x10,0x10,0x00,0x00,0x00,0x00} //T
{0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00 ,0x00,0x00,0x00,0x00,0x00,0x00} //Space
};