Forums

Again what is wrong in this quad timer???

Started by Unknown August 24, 2004
Hi! i couldt solve my timer problem... my old message
is below.....and now i am sending all project in
attachment.is there anybody who can try this code in
his/her 56f8300 demo board........
(i have downloaded code to the board and read these
values from timer variable respectively 59505,
45725, 41337, 63919. i have tried all timer
variants(timera1-a2-a3 and timerc...).all same.... but
i have build a small led blinking project using
TerInt - periodic interrupt bean.it is ok. my timer
still vorking properly with this project...)

Regards.....

isa //******************my old
message****************************************
Hi. to understand working of the quad timer i have
written this little software:

//code begins
unsigned int cnt1;

void main(void)
{
/*** Processor Expert internal initialization. DON'T
REMOVE THIS CODE!!! ***/
PE_low_level_init();
/*** End of Processor Expert internal
initialization. ***/

/* Write your code here */
PESL(TMRA0, QT_WRITE_CONTROL_REG, 0b0011000000000000);
PESL(TMRA0, QT_WRITE_COMPARE_REG1, 0xFFFF);

while(1)
{

PESL(TMRA0, QT_WRITE_COUNTER_REG, 0);
cnt1 = PESL(TMRA0, QT_READ_COUNTER_REG, ...);

PESL(TMRA0, QT_WRITE_COUNTER_REG, 0);
cnt1 = PESL(TMRA0, QT_READ_COUNTER_REG, ...);

PESL(TMRA0, QT_WRITE_COUNTER_REG, 0);
cnt1 = PESL(TMRA0, QT_READ_COUNTER_REG, ...);

PESL(TMRA0, QT_WRITE_COUNTER_REG, 0);
cnt1 = PESL(TMRA0, QT_READ_COUNTER_REG, ...);

}

}
//code ends

my aim:

clear timer
read timer
clear timer
read timer
clear timer
read timer
clear timer
read timer

i am reading cnt1 register by putting breakpoints. But
in every reading it has different value. i have just
tried and read these values respectively:
21354-28481-38797-56163.....logically i have to read
same numbers from the timer. Because i am clearing it
before every reading. And i have to read small numbers
because i am immediatly reading timer after clearing.
What is my mistake????

Regards..................

__________________________________

Attachment (not stored)
timertrouble.zip
Type: application/x-zip-compressed


Hi ....i have solved the my (foolish) problem......i
want to explain here ...
While(1){
(B)Write timer 0
(B)Read timer
(B)Write timer 0
(B)Read timer }
here (B) is the break point ....until codewarrior stop
the processor in breakpoint counter continues to
count.....this is the problem.....when i proper the
break points like that i understood the problem.....
While(1){
(B)Write timer 0
Read timer
(B)Write timer 0
Read timer }

And i have a new question...what about optimization
level.......in this application i have seen different
result in different optimization levels.....how we can
we know which level is appropriate for our
application?...

_______________________________


Hey

 

Trying to access some memory, now it’s a char * array, now memory (physical) seems to be word aligned, but I should be able to access a character at the end of the word..

 

Say, at 0x1DA3 (location) I have two bytes, 0x2C and 0x00, now my pointer is starting at character 0x00, but when I try to read from there on, by pointing a byte structure to it, it jumps back a byte and starts from the start of an address, so the first character is 0x2C…

 

Anyway I can point a byte structure in the middle of a location? Assumed it would just be possible using byte structures and pointers but inherently it wants to align to the word…

 

HELP..

 

 

 

Rajesh Singh

r...@shockdesign.com.au

www.shockdesign.com.au




Hello Rajesh

From my understanding, the compiler will generate the code for word
access when using a (word *) pointer, but you can force byte access if
you type-cast it to a byte pointer.
If SomePtr points to a structure with words in it, probably everything
in that structure is word-aligned, so to get the byte address you would
access it by putting
(byte *)SomePtr = ... .

Hope this is correct!
Robert

On 10.09.2004, at 07:36, Rajesh Singh wrote:

> Hey
>
> Trying to access some memory, now its a char * array, now memory
> (physical) seems to be word aligned, but I should be able to access a
> character at the end of the word..
>
> Say, at 0x1DA3 (location) I have two bytes, 0x2C and 0x00, now my
> pointer is starting at character 0x00, but when I try to read from
> there on, by pointing a byte structure to it, it jumps back a byte and
> starts from the start of an address, so the first character is 0x2C
>
> Anyway I can point a byte structure in the middle of a location?
> Assumed it would just be possible using byte structures and pointers
> but inherently it wants to align to the word
>
> HELP..
>
> Rajesh Singh