Saving Variables

Hi,

I am working on a simple trigger audio application. In my code I have it so that I can adjust delay with one up (longer) and one down (shorter) delay button. What I want to do is when both buttons are pushed have it save the value of the delay variable to the microcontroller, so that when the microcontroller is restarted it will load this value for the delay rather than having to reset it every time. If this is possible how would I write the code for it and include it in my project.

Thanks for the help,
Michael

Hello Michael,

M>What I want to do is when both buttons are pushed have it save the value of the delay variable to the microcontroller, so that when the microcontroller is restarted it will load this value for the delay rather than having to reset it every time. If this is possible how would I write the code for it and include it in my project.<<

Well, you can save it in Eprom and load it from beginning. Here is a Psuedo code:

HoldVar Var byte
Button1 Var Port A.0
Button2 Var Port A.1

Read 0, HoldVar ;put EEprom in HoldVar

Loop:
if Button1=1 then
pauseus 100
If Button2=1 then
Write 0, HoldVar
HoldVar=HoldVar -1
Pause 100
endif
HoldVar=HoldVar+1
endif

if Button2=1 then
pauseus 100
If Button1=1 then
Write 0, HoldVar
HoldVar=HoldVar +1
Pause 100
endif
HoldVar=HoldVar-1
endif

Do whatever you want....
goto Loop

The Pauseus and Pause can be varied to a value that works for you...
I know there are other ways to do this *=} But have fun.

Dwayne

Thanks for the help Dwayne,

I have a new question concerning your idea of writin to the eprom. Can you save over the same space in eprom? Also, can you write to the eprom inside your program?

Looking at your code you have the write command I assume to write to the eprom, however, is that writing over the same memory location in the eprom to prevent from filling all the memory with variables delay times?

I need to be able to save the holdvar variable periodically in the program at different values. If I can simply write and rewrite to the same memory spot in the eprom from the program and then read the variable on startup then this will take care of all my problems.

Thanks,
Michael

Hello Tear,

Tear>>I have a new question concerning your idea of writin to the eprom. Can you save over the same space in eprom? Also, can you write to the eprom inside your program?<<

Yes to both...You can overwrite your Eprom time and time again... and you can also write to your Eprom inside your program. The simple "Write" command does it.

Tear>>Looking at your code you have the write command I assume to write to the eprom, however, is that writing over the same memory location in the eprom to prevent from filling all the memory with variables delay times?

Yes, it is...

Write 0, Holdvar... it is writing over location "Zero" of the Eprom... You can change this to 1, and write over Eprom position #1, without affecting #0.


Tear>>I need to be able to save the holdvar variable periodically in the program at different values. If I can simply write and rewrite to the same memory spot in the eprom from the program and then read the variable on startup then this will take care of all my problems.<<

Then your problems are solved <smile>... This is exactly what is happening. I will send you a "Bill" for one handshake and one smile the next time I get to see you in person;=}

Remember the Pauseus and Pause are "timing" pauses. That computer chip is moving at a scorching speed. So you need a small amount of time for a human being to have both buttons pressed "exactly" at the same time. The Pauseus allows for this human error. Then you need a pause, so that the counter doesn't count from 1 to 256 in less time it takes to blink a eye. Thus the Pause is used to vary that. Maybe count by "1"'s every 1/10 of a second? Or you can put a "check" in there and do the following:

if Button1=1
HoldVar=HoldVar + 1
pauseus 100 (debouce that I forgot to add <g>)
endif.
while Button1=1 wend.

What this does, is only count 1 at a time, until you "release" button1. The chip will be in a infinite Loop until you release the button. That way, you can press the button really fast to make the HoldVar increase or decrease.

Dwayne

Thanks Dwayne,

This information has solved my program perfectly! I am more than happy to extend that handshake next time we meet!