PM Asembler and Melab U2 Programmer Problems with PIC16F1939

[rsocor01]

Bogdan,

Tonight I will check to see what software version I have. I bought my U2 programmer about two years ago, so it is probably an old version. I need to research this issue a little bit more.

Mister_e,

It is very nice to see you back . I have a program >8000 words that I developed using PM. This program uses interrupts on a PIC16F727 to read values for a built-in capacitance touch sensor. However, if I use MPASM the sensors don't work properly. I suspect it has to do with different interrupt intervals if I use MPASM, but I haven't tested this yet. This is the reason why I use PM for my touch sensor projects.

Robert

[mister_e]

Or it's working as design with MPASM, but have problem with PM, but... ya never know.

Do yourself a big favor, isolate the problem, keep the ISR and a simple short and sweet main loop, see if the problem's still there.

Usual Convention: Keep the ISR as short as possible.


Get rid of PBP interrupt and use ASM one, or DT.

Maybe not a bad idea to make sure you're using the latest MPASM version.

[rsocor01]

Bogdan,

I have an old software version 4.23. In Melabs.com they have a free download for the latest Beta v4.32 software. I will install it and will post back with results.

Mister_e,

Yes, I know that I have to fix that problem with the interrupts to make the sensors work properly with MPASM. Now, I am using ON INTERRUPT GOTO ISR to handle the ISR. There are many lines of code that need to get done in the ISR routine. So, if I have many lines of PBP in the ISR routine, what method should I use?

Should I go with something like this?

@myint                  ; create myint label
.......
   @ retfie  FAST       ; Return with 'auto restore' of WREG, STATUS and BSR

Or, should I do something like this with DTs interrupts?

INCLUDE "DT_INTS-14.bas"     ' Base Interrupt System
INCLUDE "ReEnterPBP.bas"     ' Include if using PBP interrupts

ASM
INT_LIST  macro    ; IntSource,        Label,       Type, ResetFlag?
			INT_Handler   TMR0_INT,  _MyInterrupt,   PBP,  yes
	endm
	INT_CREATE               ; Creates the interrupt processor
ENDASM

@ INT_ENABLE  TMR0_INT      ; enable Timer 0 interrupts

.....

MyInterrupt:                       
.....
@ INT_RETURN

[mister_e]

If you have PBP lines in your ISR, I'd say go for your second example.

What kind of interrrupt it is? Remember that ON INTERRUPT will jump in your ISR ONLY after finishing a x current job. So if you have, say PAUSE 5000, in your main loop, it may take up to 5 secondes to jump in the ISR (assuming your main loop is actually doing the PAUSE). Maybe why your sensor doesn't work that good. Now why better on PM than MPASM, I don't know.

[rsocor01]

The new U2 programmer software version supports all the PIC16F193x. So, I was able to program my 16F1939 .

What kind of interrrupt it is? Remember that ON INTERRUPT will jump in your ISR ONLY after finishing a x current job. So if you have, say PAUSE 5000, in your main loop, it may take up to 5 secondes to jump in the ISR (assuming your main loop is actually doing the PAUSE).

The interrupts that I'm using are kind of complicated (at least for me ). To make the Capacitive Sensors to work a value needs to be read from TMR1L and TMR1H together. This would tell you if the sensor was touched or not. However, the interrupt overflow is determined by TMR0. This is the way is done in the Application Notes. The interrupt settings for a 16F727 look something like this and it works,

OPTION_REG = %11000011       'Bit 2-0, 110= prescaler rate 1:16 (TMRO INTERRUPTS EVERY 1.024 mSec)
T1CON = %11000101            'Timer1 initialization
T1GCON = %11100001           'Timer1 gate init /Toggle Mode/TMR0 time base
PIR1.7 = 0                   'Clear Gate Interrupt Flag. Timer1 gate is active (TMR1GIF BIT)
PIE1.7 = 1                   'Disable the Timer1 Gate Acquisition complete interrupt (TMR1GIE BIT)

TMR0 = 0			  'TMR0 overflows every (256-TMRO)*(Prescaler rate)(4*(1/16)uS)=1024uSec.

ON INTERRUPT GOTO ISR
INTCON = %10100000		'Enable Interrupts

DISABLE			'Disable further interrupts
ISR:    
    T1CON.0 = 0                 'Stop/Clears Timer1 before reading TMR1

....

"Read TMRL and TMRH"

....

    TMR1L = 0               'Reset Timer1
    TMR1H = 0
    T1CON.0 = 1             'Restart/Enable Timer1 (TMR1ON BIT)
    TMR0 = 0                'RESET TMR0 TO 0 
    INTCON.2 = 0	          'Re-enable TMR0 interrupts. Bit 2, 0= clears overflow, 1= overflow ocurred 

    RESUME				    'Return to main program
    
    ENABLE				    'Enable interrupts

[Darrel Taylor]

Byte_Butcher was working on Capacitive Touch on a 727 with DT_INTS here ...
http://www.picbasic.co.uk/forum/show...1611#post71611

I'm not sure what needs to be changed for the 1939, but it's probably a good start.

DT

[rsocor01]

Darrel,

My program is working fine with the 16F727 and the 16F1939 as it is. But, I think it will run a lot smoother if I use the DT interrupts .

The amount of time that the chip takes between ISRs is very critical for the CSM (Capacitive Sensing Module) to work properly. So, please excuse my next dumb question . Can I say that I have a much better control of the interrupt intervals using DT interrupts than using ON INTERRUPT? And why?

Robert