Post by thread:Help with Interrupts using Timer1

Hello, This is the first time I'm attempting to use interrupts and I could use a little help........ I'm using a PIC16C63 and would like to use interrupts with the timer1 module. I would like an interrupt routine to do something every 1 second, so I am using a 32.768KHz crystal between RC0 and RC1 and using a prescale of 1:2. I have set up the program something like the following but I do not seem to be getting the interrupt. Can someone please comment on what I may be doing wrong. Thanks Randie ===================================================================== org 0x0000 goto start ===================================================================== org 0x0004 ;interrupt address bcf intcon,7 ;disable global interrupts movwf _w ;save w movf status,w movwf _status ;save status movf fsr,w movwf _fsr ;save fsr call isr ;do interrupt routine movf _fsr,w movwf fsr ;restore fsr movf _status,w movwf status ;restore status swapf _w,f ;restore w without affecting status swapf _w,w retfie ;exit and re-enable global interrupts ======================================================================= start ;main program ..... call isr_init ;intialize interrupts call timer_init ..... ======================================================================== isr_init movlw b'11000000' ;enable global & peripheral interrupts movwf intcon bcf pir1,tmr1if ;clear tmr1 overflow interrupt flag bsf pie1,tmr1ie ;enable tmr1 overflow interrupt return ========================================================================= timer_init movlw b'00011111' ;1:2 prescale,osc ena,async,extl clk,start timer movwf t1con,f return ========================================================================== isr ;interrupt routine movf pir1,w ;check for tmr1 overflow andlw b'00000001',w ;mask everything but tmr1 overflow btfss status,z goto yes_ov goto no_ov yes_ov ... ;timer1 overflow.....do so do this ... ... goto end_isr no_ov ... ;no timer1 overflow.....so do that ... ... end_isr bcf pir1,tmr1if ;clear tmr1 overflow interrupt flag return

At 14:14 16/11/98 -0800, you wrote: > org 0x0000 > goto start > org 0x0004 ;interrupt address > bcf intcon,7 ;disable global interrupts Not necessary- global interrupts are disabled when ISR received >From 16C7X "Interrupts" documentation:- "When an interrupt is responded to, the GIE bit is cleared to disable any further interrupt" {Quote hidden}>start ;main program > ..... > call isr_init ;intialize interrupts > call timer_init > ..... > >======================================================================== >isr_init > movlw b'11000000' ;enable global & peripheral >interrupts > movwf intcon Problem may be because you are enabling interrupts before setting the timer up? Have you tried doing both your init routines, _then_ setting GIE? > bcf pir1,tmr1if ;clear tmr1 overflow interrupt flag > bsf pie1,tmr1ie ;enable tmr1 overflow interrupt pie1 is in Bank 1, so you need to change STATUS,RP0 or use indirect addressing either bcf pir1,tmr1if ;clear tmr1 overflow interrupt flag bsf STATUS,RP0 bsf pie1,tmr1ie ;enable tmr1 overflow interrupt bcf STATUS,RP0 or bcf pir1,tmr1if ;clear tmr1 overflow interrupt flag movlw pie1 movwf FSR bsf INDF,tmr1ie ;enable tmr1 overflow interrupt Hope that helps, Nigel -- Nigel Orr Research Associate O ______ Underwater Acoustics Group, o / o \_/( Dept of Electrical and Electronic Engineering (_ < _ ( University of Newcastle Upon Tyne \______/ \(