combined register reading

[young]

In microchip, there are a lot of pairs of registers, like (TIMER1H,TIMER1L),(TIMER0H,TIMER0L), (CCPR1H,CCPR1L), we could put high byte and low byte together like the following tow methods, right?

//this is for 18f458
#BYTE timer1h 0xFD7h
#BYTE timer1l 0xFD6h
int16 time1
timer1=timer1h<<8+timer1l;

or
union timer1{int16 t1, int8 t1[2]} T1D

T1D.t1[0]=timer1l;
T1D.t1[1]=timer1h;

timer1=T1D.t1;

right?


timer1 T1

[valemike]

not sure about the union stuff, but i always read a Timer using CCS libraries and 'unsigned long'.

e.g.
unsigned long timer_value;
timer_value = get_timer1();

[Ttelmah]

You can add:

int16 timer;
#BYTE timer=0xwhatever_you_want.

Then reading/writing 'timer', will access the whole 16bit value.
'#BYTE', locates a variable at a location, and if it does not exist, creates an int8. However if the variable already exixts of a larger type, it locates the whole larger variable at the location, and subsequent addresses. It is another useful shortcut. :-)
This is what you are seeing in the libraries with the 'unsigned long'.

Best Wishes

[Mark]

use #locate instead of #byte.

[Felix Althaus]

Hello

It's not exactly the same as orginally asked, but something similar:

What should I do, if the two bytes of a long aren't in consecutive oder. For example I want to do this:

long any_var;

any_var = counter;

counter is a long with low byte at 0xXY and high byte at 0xAB

How can I do this without #locate (I have 2.734). It seem's I can't get the trick...


Thanks
Felix

[Mark]

If a variable is a long or 16bits then it must be consecutive. I said must be.

[bluetooth]

Without asking why the bytes wouldn't be next to each other, I suggest you take a look at the CCS function make16() - you can build it up that way with the high and low bytes any where you want them....

[Ttelmah]