Instant Interrupts - Revisited

[mister_e]

And all this with a minimum of efforts

[Pic_User]

For the record (partial pasted from other thread):

Hi all, I've been trying to get Darrel Taylor's Instant interrupts to work with a 12f675 with no luck. Will they work with a 12f675?

I just get the following error message when I try to compile it:

ERROR: Variable wsave3 position request 416 beyond RAM_END 95.
ERROR: Variable wsave2 position request 288 beyond RAM_END 95.
ERROR: Variable wsave1 position request 160 beyond RAM_END 95.
ERROR: Unable to fit variable RS2_Save
<..snip...>
Thanks for any help.

Bill

See Darrel’s solution:
“To get Instant interrupts with Basic Language working on a 12F675 ...”
Open the DT_INTS-14.bas file and comment out the wsave lines. The 675 doesn't have any usable RAM in banks 1,2 or 3

' --- IF any of these three lines cause an error ?? ---------------------------- 
'       Comment them out to fix the problem ----
' -- It depends on which Chip you are using, as to which variables are needed --
;wsave1      var byte    $A0     SYSTEM      ' location for W if in bank1
;wsave2      var byte    $120    SYSTEM      ' location for W if in bank2
;wsave3      var byte    $1A0    SYSTEM      ' location for W if in bank3
' ------------------------------------------------------------------------------

Then in the ReEnterPBP.bas file comment the T?_save variables.

;    T1_Save     VAR WORD
;    T2_Save     VAR WORD
;    T3_Save     VAR WORD
;    T4_Save     VAR WORD

Just remember that if you use Instant Interrupts on a different chip later, you will need to un-comment those lines.
HTH,
__________________
DT
http://www.picbasic.co.uk/forum/show...9510#post49510

[debutpic]

Hello all

Today I play with " Instant Interrupts" thank's Darrel

For to begin I use blinky program
I want to augment the speed of blink light by loading a value
in TMR1H and TMR1L but the speed does not change

Rq:
I want not to change the value of the prescaler


code:

'********************
TMR1H = %11111111
TMR1L = %11111110
'********************

1CON = %110001 ; Prescaler = 8, TMR1ON

what is wrong please?

[Darrel Taylor]

I want to augment the speed of blink light by loading a value
in TMR1H and TMR1L but the speed does not change

code:

'********************
TMR1H = %11111111
TMR1L = %11111110
'********************

Loading that value %1111111111111110 = $FFFE = 65534
Means the timer will overflow after only 2 ticks.
A smaller number would help.

Also, it has to be loaded after every interrupt, not just at the beginning of the program.
<br>

[debutpic]

thank's Darrel

Remark:

In my next code if I load TMR1H with a high value code work fine

Main:

TMR1H = %11111111
pause 1

----------------------------

but if I reduce the value in TMR1H code don't work
display is OFF

Main:

TMR1H = %10111111
pause 1

-------------------------------
if I want use this value "TMR1H = %10111111"
I must write "pause 20" and not "pause 1"

an idea ???????

[Darrel Taylor]

No, I have no idea what you are doing.
If you're using a timer, why do you need pauses?

What frequency are you trying to run the timer at?
What frequency is your primary oscillator?
What PIC are you using?
<br>

[debutpic]

I use one 16F877 MCU to 20 Mhz

TMR1 produce an interrupt every 0,4 µSec
for to drive four 7 segment displays (prescaler:1)

My board developpement is EasyPic4

If I write not a Pause after TMR1H %11111111
then the displays don't work