Still HSEROUT woes

[mister_e]

mmm,

asm
MOVFF WREG,wsave ; copy W to wsave register
MOVFF STATUS,ssave
CLRF STATUS ; change to bank 0 regardless of current bank

INT_CODE

MOVFF R0,_R0_2
MOVFF R0+1,_R0_2+1

should be..

asm
INT_CODE
    MOVFF WREG,wsave ; copy W to wsave register
    MOVFF STATUS,ssave
    CLRF STATUS ; change to bank 0 regardless of current bank



    MOVFF R0,_R0_2
    MOVFF R0+1,_R0_2+1

[Charles Linquis]

Steve, you are absolutely correct. One of my edits went awry.

Unfortunately, when I put the INT_CODE line in the correct place,
nothing changes. Still no joy.


And mister_e,

The lines are part of my "standard" header file. I can't tell you why they
are there. Probably some legacy issue. Anyway. I took them out.
No change in behavior.

[mister_e]

O.k then i'll try again

Beeing said i already heard of some care about the Tim's routine.. i just don't remind where but.. humm.

Now i'm very bad and slow in assembler debugging so, apologies..

[mister_e]

just an idea... how about replacing the Hserout by a TXREG=Char loop. Just by seeing the output of it, it seems the routine just redo the Hserout line without keeping track of what have been already sent...

OR it have to exist a character pointer variable in the HSEROUT macro somewhere... if so, you probably didn't save it in the INT Handler... mmm interesting....

[mister_e]

pfff... maybe

    IF TimerFlag = 1 THEN
       SecondsCounter = SecondsCounter + 1
       INTCON = 0
       HSEROUT ["Seconds = ",#SecondsCounter,13,10]
       INTCON = %11100000 
       TimerFlag = 0
       Timer = 0
       ENDIF

    IF KeyHitFlag = 1 THEN
       INTCON = 0
       HSERIN [Y]
       HSEROUT[Y]
       INTCON = %11100000 
       KeyHitFlag = 0
       ENDIF

[mister_e]

ah come on brain cell (no s)... wake up...

IF INTCON.2 = 1 THEN
TMR0H = $EC ; Reload TMR0 to 65535 - 5000
TMR0L = $77
Timer = Timer + 1
IF Timer >= 1000 THEN
TimerFlag = 1
ENDIF

ENDIF

IF PIR1.5 = 1 THEN
KeyHitFlag = 1
ENDIF
INTCON.2 = 0 ; Clear the timer flag

where the PIR1.5 is cleared?

[Charles Linquis]

In the PBP program. HSERIN clears the flag.

[mister_e]

Nicely done! That show and confirm my assembler limitation and some basic register knowledge. I really have to work harder on that.

[SteveB]

Correction: The HSEROUT works as expected, the HSERIN does not. But I was really only looking at the interaction between interrupts and HSEROUT to begin with. I'll take a closer look at the HSERIN now.

Steve

[SteveB]

Well, Just moving
HSERIN [Y]
HSEROUT[Y]
into the ISR solved the HSERIN as mentioned.

Despite getting it working on my equipment, we still don't know why it isn't working for Charles. I'd like to know why the difference.

Steve

[mister_e]

well let's see it in the simplest way... an Interrupt flag have been set, it jump to the ISR but he's not clear before going out... what happen? it return back to the ISR as soon as possible.

As it's just a single character.. HSERIN can be changed to

x=RCREG
While RCREG : Discard=RCREG : Wend

or few lines of assembler...

OUF, at least i wasn't too far.. that's good for my own self esteem

[Charles Linquis]

I can deal with the requirement to read the RCREG from within the ISR, but having to shut off the interrupts while running HSEROUT is more problematic. I have to run full-duplex in my application. That is why I needed it interrupt-driven in the first place!

[Charles Linquis]

SteveB:

Confirming - I took your code and loaded it into my 8720. It works as expected, except that it doesn't handle USART interrupts (as you mentioned). I'm thinking that your routine works better because you saved/restored BSR, while I was was saving/restoring FSR0L and FSR0H.

I have an email to MELABS. Maybe they can shed some light on this.

When we are done, I think we will have a good framework for how to deal with interrupts in the 18F series!