Instant Interrupts - Revisited

[DaTiNs]

Thank you very much!

I must add TRISA = 0 to the begin of code, and then start work great.

One more time, thank you, Damir.

[SteveB]

Darrel,
While poking around and getting ideas, I got to looking at ver 1.2 of "Elapsed_INT-18.bas". I was particularly interested in the nice routine to calculate the timer reload constant:

' -------------- calc timer reload Constants -------------------------------
ASM
T1PS = 1                             ; start with 1:1 postscaler
TimerConst = ((OSC*1000000)/4/100)   ; how many timer ticks will it take
  while TimerConst > 65400           ; if it's more than the timer can count
T1PS = T1PS * 2                      ;   double the postscaler
TimerConst = TimerConst / 2          ;   halve the count
  endw
TimerConst = 65536 - TimerConst + 8  ; final reload value

But, I think there is an error in the formula. The absolute time it takes to execute the 8 instruction cycles doesn’t change. But, the time in relation to the TMR1L will be proportional to the prescaler. So, that should be accounted for in the formula, as such:

TimerConst = 65536 - TimerConst + (8/T1PS)  ; final reload value

Since it's not likely the prescaler will need to be above 1:8, the 8/T1PS shouldn’t get too low.

Thanks again for your great work and inspiring examples,
Steve

[SteveB]

The code could also be changed thus, not that it makes a difference:

T1PS = 1                             ; start with 1:1 postscaler
TimerConst = ((OSC*1000000)/4/100)+8 ; how many timer ticks will it take
  while TimerConst > 65400           ; if it's more than the timer can count
T1PS = T1PS * 2                      ;   double the postscaler
TimerConst = TimerConst / 2          ;   halve the count
  endw
TimerConst = 65536 - TimerConst      ; final reload value

[jamie_s]

Hi Darryl,

Currently getting an error with Latest MPLAB IDE:
MPLAB 8.90.00.00

PIC is an 18F45K22 and DT_INTS-18 is latest from your website, both MPLAM and DT_INTS were downloaded from the respective sites on 15/3/2013


ERROR: Unable to execute mpasmwin.Warning[206] M:\<FOLDERPATH><FILE>ASM 2170 : Found call to macro in column 1. (INT_ENABLE)
Error[116] M:\<FOLDERPATH><FILE>.ASM 696 : Address label duplicated or different in second pass (Z00032)
Error[116] M:\<FOLDERPATH><FILE>.ASM 759 : Address label duplicated or different in second pass (Z00033)
Error[116] M:\<FOLDERPATH><FILE>.ASM 812 : Address label duplicated or different in second pass (Z00034)
Error[116] M:\<FOLDERPATH><FILE>.ASM 843 : Address label duplicated or different in second pass (Z00035)

Can you advise if there is any fix for this or do i need to use an older version of MPLAB IDE

[mackrackit]

You might try here
http://support.melabs.com/threads/11...hlight=MPLAB-X

[Christopher4187]

I've used the DT_INTS sucessfully with an 18F4550. I had to move to an 18F87J50 but the DT_INTS would not compile. Not sure if I'm doing something wrong or if the DT_INTS was never tested with J series PIC's. When I compile, I get the following warning message:

Unable to fit variable VP_DelayCount in requested bank 0

In the "VirtualPort.bas" code, I changed this code:

VP_DelayCount  VAR WORD BANK0  ; Used for internal Delay only

to this:

VP_DelayCount  VAR WORD BANK1  ; Used for internal Delay only

and it compiled as expected. I have no clue if this will cause unexpected problems with my program or if this is the correct way to solve it but I haven't noticed any ill effects yet. Seems like this problem could be related to the SFR's but it's way above my level of knowledge.

Just thought I'd pass it along.

[Darrel Taylor]

NO! You can't just change the variable to BANK1!
That variable must be in BANK0.

Both DT_INTS-18 and VirtualPort.bas fit quite comfortably in an 18F87J50, with room to spare. Even when using PBPL.

How many variables have you declared in BANK0 in your program?
Or, what other include files are you using that may have variables placed in BANK0.