Hi,
I am using AT89C51rd2. When I use big arrays like abc[270] and def[274] in my code, nothing works correct. But i use abc[40] and def[40], every thing is ok.
when abc[270] and def[274] declared, keil generates:
Program Size: data=109.1 xdata=1159 code=12696
when abc[40] and def[40] declared, keil generates:
Program Size: data=109.1 xdata=695 code=12461
In options, "use on-chip xram" is checked. I tried to set AUXR resiter in firmware like XRS0=0,XRS1=0,XRS2=1 to select "software selectable" xram size as 1792. Nothing is work....
What can be the problem???
Thanks...
That's next to meaningless!
You need to describe precisely what things you are trying to do, what results you were expecting, what results you actually got, and what thought & debugging you have applied in trying to resolve the issue.
First problem, I am driving an IC and if the IC is setup correctly, my system's total current consumption should 0.17 A. But with big arrays it is 0.7 A. So this means IC is not setuped correctly by MCU.
Second problem, No uart commands works when big arrays defined...
even when the big arrays defined but "not used" (Sources\main.c(717): warning C280: 'abc': unreferenced local variable), I got these problems... (array defination: abc[275])
I tought many people get this type problems, so I think they understand the situation well...
By the way, thank you for "meaningless".
Remember that nobody on this forum knows anything about your, or your project, or your hardware, or your software other than what you clearly and explicitly state in your posts.
If you can't find the problem when you have the code and the hardware right there in front of you, how do you expect anyone to do so without seeing or knowing anything about the hardware & software?
"So this means IC is not setuped correctly by MCU"
That's good - you've made a first step!
Now you need to investigate further to find why it's not getting set up correctly.
Again, with no access to your hardware or your software, nobody else can do this for you.
You haven't even said what IC it is, or how you set it up.
"No uart commands works"
Sorry, that's meaningless again!
You're back to, "My car doesn't work - what's wrong with it?"
What are these "UART commands"? What are they supposed to do? What do they actually do? What thinking & debugging have you done in an attempt to account for the difference?
"I tought many people get this type problems"
But we don't know exactly what type of problems you are having!
There's an almost infinite number of things that could cause stuff to "not work".
Again, think about "My car doesn't work - what's wrong with it?"; how many different things can you think of that would make a car "not work" - there must be hundreds!
"I think they understand the situation well"
Only if you explain it well!
You have identified that the presence/absence of "big arrrays" seems to affect this - so you need to investigate what, exactly, is different.
Have you tried this in the Simulator?
Here are some debugging tips & techniques:
www.8052.com/.../120313
www.techonlineindia.com/.../Developing_a_good_bedside_manner.aspx
hey mustafa.
my project had a simelar problem in start. i have been coding for nearly 5 months and have lots of many experience and write very complicated code {it needs comments !!!!!} but not even i can answer your question. you have more memory ?????
tan.
if I recall the RD2 has 756 bytes of XDATA check the datasheet
Erik
I think its not an application specific issue, because when I define a variable which is not used in code and when it exceed 768 byte xram, it starts to make problem. It look like a memory allocation problem, and indirect addressing does not work good for exceeding 768bytes.
In the At89C51Rd2's datasheet, it says, xram set 768 bytes at reset but it is software configurable up to 1792 bytes. So i tried to set AUXR resigter as XRS0=0, XRS1=0, XRS2=1 but it did not work...
Am I wrong? I am expecting a way to solve this problem...
Thanks for replies...
when I define a variable which is not used in code why do you "define a variable which is not used in code"
and when it exceed 768 byte xram, it starts to make problem. how do you see that "it starts to make problem" also see below
It look like a memory allocation problem, and indirect addressing does not work good for exceeding 768bytes. it does not matter if addressing is indirect or not, if the memory is there
So i tried to set AUXR resigter as XRS0=0, XRS1=0, XRS2=1 but it did not work... where in the code, hopefully in startup.a51. also what is the XDATA size set to
Am I wrong? I am expecting a way to solve this problem... expecting??
-why do you "define a variable which is not used in code"- to test if does it make a problem.
-how do you see that "it starts to make problem" also see below- For example, xdata=900, it make small problems. Uart commands answers back but not true. For xdata=1159, nothing works, no answer...
-it does not matter if addressing is indirect or not, if the memory is there- it was just a opinion.. ;)
-where in the code, hopefully in startup.a51. also what is the XDATA size set to- at the beginning of the main. i did not know that startup code make this.
So...?
-how do you see that "it starts to make problem" also see below- For example, xdata=900, it make small problems. Uart commands answers back but not true. For xdata=1159, nothing works, no answer... that is rather arbitrary that "something falls apart when I'm doing something else" is about the most worthless diganostic there is make a piece of code that writes and reads back from, say address 500, then address 1000
i did not know that startup code make this.
make it do it
I would not be surprised if selecting RD2 automatically set it for 756 bytes
just a note
make a renamed copy of startup.a51 and include it in your project
Finally problem is solved.. :)))
Firstly I had change just XDATA lenght, but it did not work. Then I tried to add some assembly code at the beginning of the place which XDATA space cleared in startup.a51. Then is OK...
Thanks for all replies.....
Here is the code that I added:
This code set AUXR to 1792 bytes XRAM....
XDATALEN EQU 1792 IF XDATALEN <> 0 mov a,8EH setb acc.4 clr acc.2 clr acc.3 mov 8EH,a MOV DPTR,#XDATASTART MOV R7,#LOW (XDATALEN) IF (LOW (XDATALEN)) <> 0 MOV R6,#(HIGH (XDATALEN)) +1 ELSE MOV R6,#HIGH (XDATALEN) ENDIF CLR A XDATALOOP: MOVX @DPTR,A INC DPTR DJNZ R7,XDATALOOP DJNZ R6,XDATALOOP ENDIF
Well done, and thanks for sharing the solution - too many people never bother to do that.
:-(
In your very first post, you said,
"I tried to set AUXR resiter in firmware like XRS0=0,XRS1=0,XRS2=1 to select 'software selectable' xram size as 1792. Nothing is work...."
So what was the difference between what you tried then (that didn't work), and what you have done now (that does work)?
before, I wrote the code to set AUXR in (beginning of) main (as C code), and it did not work... but then I made it in startup and it is ok...
Do you now understand why that's a bad idea?
It would also be a goos idea to comment your additions to the startup file - both to remind yourself why it's there, and what it does...
I do not understand what was the bad idea?