i am facing a wierd problem.. My MCU P89V51RD2BN resets during Execution... i am a college student and a beginner Here so i dont know the Advanced Programming methods i would also inform that..
i have a recursive function , a warning is issued by the compiler for the same. but....
earlier this was not a problem but since i have modified some of the Sub-Routines for 16Bit Data this Problem has come up, i need those functions to be 16 bit because of the limitation of the ALU i was earlier using 8bit and leaving most of the Task to Assumption which i cannot do so now..
i would also state that the Problem occurs in a fumction at a point when i call 2 functions in the same code, these themselves call around 5 sub-routines each but that wasnt a problem earlier (before i used the 16bit return type sub-routines).
now i found something in the manual stating reentrant Functions, but i really dont know how to use it
i used it like this
void Home_Screen_Instance() reentrant { ------------ } Do i need to use the keyword "reentrant" in the Function Decleration too? but that didnt help either but the compilers shows an error Home_Screen_Instance : redefinition. Target Not Created
this was the first of a kind problem that i encountered, my MCU is resetting itself for sure(i checked that with a dummy subroutine of blinking LED) and it is not because of the watchdog timer, i am sure about that too..
so whats the Problem here?
is the Stack overflowing??? or there is any other reason behind this? should i revert back to the 8bit versions of my subroutine (without any other choice)? is it because of the recursive nature of the function H0me_screen_instance?
Related Data:
The Program is Display intensive, i mean there are a lot of Strings to be displayed and they are stored beforehand in XDATA, message shown during sucessfull compilation, (still resets) Program Size: data 9.4 xdata 252 code 9514 creating hex-----blah blah blah---- 0 Error(s) 65 Warning(s)
what you are trying to overcomplicate has been done in very simple ways many, many times before.
Erik
sum = 0 for >max if !digit break sum *10 sum += digit
Note of course that the pseudocode for storing the digits in a integer do require an integer of proper size.
So an unsigned 8-bit variable have max range 255 and room for 2 digits. An unsigned 16-bit variable have max range 65,535 and room for 4 digits. An unsigned 32-bit variable have max range 4,294,967,295 and room for 9 digits.
In this specific case, a signed 8, 16 or 32-bit integer will have room for the same number of base-10 digits, allowing the function to return -1 for cancel or a value >= 0 for a properly entered number.
It takes many machine-code instructions to perform a 32-bit divide (for handling "backspace") but the C code will be very clean, saving coding and debugging time.