memory bank, program malfunctions on micrcontroller

[AslanPeter]

using p69c688 : 8051 micrcontroller
As i have run out of registers, i am using memory locations to store the values of some variables. i am using the memory bank

30 to 7h. my code simulates as expected however it does not run correctly on the micrcontroller. i am reading a data from a

peripheral. i probed with oscilloscope its signal at my micrcontroller port, it is as expected in my program. however my

output is badly synchronised and does not work as expected although it simulatedsfine. any tips please because i am not able

to fix it. i have found the following , which may be the cause of my problems although i don't understand what the author

means by system stack

General Purpose RAM: 30h to 7Fh
These 80 bytes of Internal RAM memory are available for general-purpose data
storage. Access to this area of memory is fast compared to access to the main memory
and special instructions with single byte operands are used. However, these 80 bytes
are used by the system stack and in practice little space is left for general storage. The
general purpose RAM can be accessed using direct or indirect addressing modes.
Examples of direct addressing:

I am using RIDE for simulation and WinISP to download the configuration
cheers

 

[millwood]

I for one would be interested to see how it simulated fine but didn't work in real life.

i don't understand what the author

means by system stack

that's an area of the memory that you should NOT mess with, as the quoted paragraph clearly showed.

 

[AslanPeter]

but SP is initliased at address 08according to the same reference. i don't understand what he means by system stack and what it is for.

 

[jumper2high]

Call stack - Wikipedia, the free encyclopedia

Quick and simple explanation

 

[millwood]

Quick and simple explanation

in summary, a memory area that you should NOT mess with.

 

[jumper2high]

He may not be able to use it, but that doesn't mean he shouldn't try to learn at least the most basic stuff about it.