Troubled with Instant Ints and TMR2

[Darrel Taylor]

Still cant get my 125us interrupt with 4Mhz internal OSC this should be possible unless DT´s routines take more than 125 instructions to work (just my guess),.. Patience....Again i am sure HE knows

This page might explain it.
http://darreltaylor.com/DT_INTS-14/kudos.html
Especially the last paragraph.
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[Josuetas]

So Darrel if i made this with just an ASM interrupt i would be able to get my 125uS since i wouldnt need the Reenter Context Saving...


BUT please o please can you help me?..

I use to get to this point where: i dont know any assembler!!!
even worst
A bit Array of 120 samples in Assembler .... mmm..... mmmmm....

By the way would you consider (in my case) the pauseus 125 Take Sample option?

Please some lead to solve this matter.

Thanks again

DJC

[Darrel Taylor]

>> So Darrel if i made this with just an ASM interrupt i would be able to get my 125uS since i wouldnt need the Reenter Context Saving...
Correct.

>> A bit Array of 120 samples in Assembler .... mmm..... mmmmm....
In ASM, you would just shift the bits into a byte var. After 8 bit's move to the next byte. After 15 bytes you're done.

>> By the way would you consider (in my case) the pauseus 125 Take Sample option?

YES!
Your program just sits in a loop anyways, waiting for the sample to finish.
No need to use interrupts, if it's not doing anything in the first place.

Or, you can still use the timer. Just poll the TMR2IF Flag.
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[Josuetas]

I will keep working on the interrupt option... This is supposed to detect DTMF (we talk about it before) so for it to work in the background of anything else is the best choice.

Everything is so complicated in ASM!.. thanks god there is picbasic.

[Darrel Taylor]

Here's a quick untested stab at an ASM handler.

Change the Handler type to ASM

Samples      VAR BYTE[15] BANK0 SYSTEM
SamplePTR    VAR BYTE     BANK0 SYSTEM
SamplesAddr  CON EXT
@SamplesAddr = Samples
BitCount     VAR BYTE     BANK0 SYSTEM
ByteCount    VAR BYTE     BANK0 SYSTEM
FlagSample   VAR BIT
TMR2ON       VAR T2CON.2

;----[Start getting the 120 samples]------------------------------------------
GetSamples:
    FlagSample = 0
    SamplePTR = SamplesAddr
    ByteCount = 15
    BitCount  = 8
    PR2 = 125 : TMR2 = 0 : TMR2ON = 1
return
    
;----[TMR2 Handler]-----------------------------------------------------------
ASM
Sample
    MOVE?BB  SamplePTR, FSR      ; Load FSR with pointer to array
    MOVE?TT  CMCON,7, STATUS,C   ; Put sample in carry flag
    rrf      INDF, F             ; Shift in the sample bit
    decfsz   BitCount, F         ; Are all 8 bits in ?
    goto     Int_Done            ;   NO, done for now
    MOVE?CB  8, BitCount         ;   Yes, reset bitcount
    incf     SamplePTR, F        ;     Point to next byte
    decfsz   ByteCount, F        ; Are all 15 bytes done ?
    goto     Int_Done            ;   NO, done for now
    MOVE?CT  1, _FlagSample      ;   Yes, Indicate - Samples Complete
    MOVE?CT  0, _TMR2ON          ; stop the timer
Int_Done
    INT_RETURN
ENDASM

[Josuetas]

Your wish to help is INFITE and appreciated Darrel.

Thanks Again

[Darrel Taylor]

Ha!

You are using ....

LCD_AnyPin
Instant Interrupts
Elapsed Timer

and you showed your "Colors" when posting.

How could I possibly Not Help??
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