asm interrupts

[Macgman2000]

I dropped in a segment of your configuration setup and still not even a simple toggle of an I/O port. I don't see the problem


@ device HS_OSC, LVP_OFF, WDT_OFF
; @ Device pic16F877A, HS_OSC, BOD_OFF, PWRT_ON, WDT_ON, PROTECT_OFF

DEFINE OSC 20
' Set Debugin pin port
DEFINE DEBUGIN_REG PORTC
DEFINE DEBUG_BAUD 4800
' Set Debugin pin bit
DEFINE DEBUGIN_BIT 7
' Set Debugin mode: 0 = true, 1 = inverted
DEFINE DEBUGIN_MODE 1

DEFINE INTHAND myint

' Configure internal registers


TRISD = %00000000
TRISC = %00000000
CMCON = %00000111 ' Comparators OFF to allow inputs on pins
PIE1 = %00000001 ' enable TMR1 overflow interrupt
PIE2 = %00000000
PIR2 = %00000000


T1CON = %00100000 ' stop TMR1
PIR1.0 = 0 ' clear bit 0 TMR1 interrupt flag
TMR1H = $8C
TMR1L = $A0 ' loads 36000 - gives 24 mS on CRO
T1CON = %00100001 ' start TMR1



wsave VAR BYTE $70 system ' Saves W
ssave VAR BYTE bank0 system ' Saves STATUS
psave VAR BYTE bank0 system ' Saves PCLATH
fsave VAR BYTE bank0 system ' Saves FSR


servo1 VAR byte bank0
servo2 VAR byte bank0
servo3 VAR byte bank0
servo4 VAR byte bank0

chksum1 var byte bank0
chksum var byte bank0

sv01 var byte bank0
sv02 var byte bank0
sv03 var byte bank0
sv04 var byte bank0

portc.0=0
goto mainloop


asm

; Save W, STATUS and PCLATH registers, if not done previously
myint movwf wsave
swapf STATUS, W
clrf STATUS
movwf ssave
movf PCLATH, W
movwf psave



; Save and restore FSR and any other registers used

bCf portc.0

movf 127,w
movwf _servo1
movwf _servo2
movwf _servo3
movwf _servo4

; Restore saved registers
movf psave, W
movwf PCLATH
swapf ssave, W
movwf STATUS
swapf wsave, F
swapf wsave, W

retfie ; Return from interrupt

endasm



mainloop:
pause 100
portc.0=1
goto mainloop

[skimask]

I don't see anything clearing interrupt flag!

[Macgman2000]

I do clear it at the top. Do I have to clear it while inside the interrupt routine?

[skimask]

I do clear it at the top. Do I have to clear it while inside the interrupt routine?

Where do you clear the Timer 1 interrupt flag at the top?

Refer to the PIC16F877A datasheet, DS39582B-page 26

[Archangel]

I do clear it at the top. Do I have to clear it while inside the interrupt routine?

When interrupt fires it sets a flag bit and will not fire again until reset in ISR, that's The word according to my 3 bottles of Miller High Life anyway

[Macgman2000]

I clear it here

T1CON = %00100000 ' stop TMR1
PIR1.0 = 0 ' clear bit 0 TMR1 interrupt flag
TMR1H = $8C
TMR1L = $A0 ' loads 36000 - gives 24 mS on CRO
T1CON = %00100001 ' start TMR1

joe, I think you answered my question. It does have to be in the ISR.
So syntax..... bcf PIR1.0m will this work?

[skimask]

You clear it at the beginning, find...but it's likely not set at the beginning...
What happens when the flag gets set during program execution?
Refer to the datasheet!

[skimask]

When interrupt fires it sets a flag bit and will not fire again until reset in ISR, that's The word according to my 3 bottles of Miller High Life anyway

Almost, but I think the wording should be 'will continuously fire'...in other words, if the flag stays set (or clear as the case might be), the program returns to the main loop and gets interrupted again straight away.
But then again...I would never doubt the word of a select beverage...