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Scrolling text on a Dot matrix display...


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Wow.. what logic do you use for scrolling? Keep a buffer and shift left?

Very nice work and thanks for the credit roll.

 

very simple.... I started with my seven segment display driver routine. Buffer for display data to be sent out, just scan the buffer over and over. And send the data out to the shift registers, this way don't have to worry about what the display is doing so much as just write to the buffer.

 

Then just have to change the data in the buffer.... I shift left data in the buffer, new data enters last buffer byte.

 

// Scroll test

for(t=0; t < 44; t++) // Length of my text message

{

for(l=0; l < 6; l++) // my characters are 5x7

{

for(i=0; i < 7; i++) // shift left data bytes in buffer. I am using 8x8

{

display_buffer = display_buffer[i + 1]; // shift left byte

}

display_buffer[7] = ~Font8x5[scroll[t] - 32][l] & 0x00ff; // load right most buffer with next line of character. Convert ASCII offset for the data by subtracting 32.

__inline__delay(10000); //Scroll speed

}

}

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Good work! I was attempting something similar, but I wanted to stick with my existing letter formatting, which meant I would have to pass an array to a function. I might have another go now, seeing yours working so nicely has spurred me on.

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I have a link to the source code on my youtube page. I using a ASCII 5X7 Character set I found in the internet, and because of memory limitations on the Micro that comes with the Launchpad(other MSP430's have little more memory). I had to trim it down some, also found using some standard C functions eat up to much RAM, so making some trimmed down ones or just write code to do only what you need.

 

As someone pointed out function calls use RAM, so if you call too many you can end up running out of RAM.

I want to write a trimmed down printf type routine, always a choice between neat looking code and code that will fit into the limited memory space.

 

 

 

Good work! I was attempting something similar, but I wanted to stick with my existing letter formatting, which meant I would have to pass an array to a function. I might have another go now, seeing yours working so nicely has spurred me on.
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hi guys I have a project at univercity for my 'microprocessor' lesson.I need this project to pass this lesson so can someone send me it's c code and proteus circuits please?

 

 

Added C code and schematic to my web page...

 

http://www.youtube.com/redirect?q=https%3A%2F%2Fsites.google.com%2Fsite%2Fericstringer%2Fhome%2Fprojects%2Fmsp430launchpad%2Fdotmatrix-scrolling-text-demo&session_token=zHysJf8hdqhGYrFCGEUNI6hK52J8MTMwNTMzNTk4M0AxMzA1MjQ5NTgz

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While compiling the program there is a fatal error which is 'Fatal Error[Pe1696]: cannot open source file "io.h" C:\Users\FERHAT\IAR\main.c 4 ' Is there anyone can help me about this problem.

 

I am using Linux gcc to compile my programs, a small change will be needed if your using the TI compiler under Windows.

 

I think you don't need the io.h under Windows TI compiler, try it without it.

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  • 6 months later...

Hi there,

i did try it out on windows 7 VM ,as I am a Mac user. I did remark the io.h and the outcome is about 11 errors and 10 warnings. I use Code Composer Studio v4 (free) on win dose virtualized. However, I still have the native msp430-gcc v4.5 on my OS X. Could you please share the make file or the complier option you use for 2231 or 2211? It is exactly the same procedure like on the linux.

Thanks in advance! I hope you are still available here, as the thread is quite old....

Cheers!

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