problem related to resource sharing , #locate , #reserve,ISR

[rohitd]

Hi ,
I am facing problems in using the interrupts (occurring every 0.2ms) along with the LCD display module.

When I disable the interrupt of timer3 occurring every 0.2ms then my LCD module is working fine, but when I enable this interrupt my LCD shows garbage data.

I am using my own version of sprintf for writing the variable values into buffer to make sprintf bit fast.

Following are the code lines

[Ttelmah]

First, the in house' sprintf, will function in a completely different way to yours. You can't generate pointers to constant strings in CCS, in the default configuration, so the compiler will ignore the pointer cast, and instead use the CCS 'shortcut', extracting the characters from the constant, one at a time, not using the string functions at all. You don't show your sprintf, so we can't see what may be wrong with it.
The 'odds' are that the problem is not where you think it is. A typical 'guess', would be:
The string passed by your function, is not null terminated properly. You 'get away' with this without the ISR, but the ISR changes something further down in memory (where it is legitimately working), and makes this show a problem. Remember that your sprintf, when it gets to the null terminator, must copy this as well. Also, triple check your sizes, remember that when dealing with strings, you must always allow space for the extra terminator character. The situations you describe, where things do work, are all ones, where the compiler will have correctly terminated the strings....
The ISR, in CCS, is extremely good at not changing anything used elsewhere. They spend a lot of effort (too much a lot of the time....), saving _every_ register, before executing the ISR code, and restoring these afterwards.
You can go DIY for the ISR. You don't need locate, or reserve. Just declare an int_global, have it save every register into a static memory array. Then test what interrupt has triggered, and call the corresponding subroutine, when this returns, restore all the registers, and you have duplicated the functionality of the CCS code, and gained nothing......
The only reason for the ISR overwriting anything, or the main code behaving as if this is happening, is that something in your code (either in the ISR, or in the main), _is_ using values outside the memory areas reserved for it. Using locate and reserve, won't stop this, you need to find what is doing it. String/array operations (the former in particular, if the terminator is missed), are the 'classic' operations to do this......

Best Wishes