Post by thread:[PIC]: Timer

Hi I am looking for a chip or chips that can do the following: - Act as a digital clock,(hours and minutes) the time must be able to be set externally. - Run 4 seven segment displays, to display the time (HH:MM). - Have 1 or 2 alarms that can be set to activate external circuits at a certain time. Any help with finding a chip that can do this will be greatly appreciated. Thanks Saurabh -- http://www.piclist.com hint: To leave the PICList spam_OUTpiclist-unsubscribe-requestTakeThisOuTmitvma.mit.edu>

There is a program in the 1995.1996 ECHB UPDATE I book that is almost exactly that. It even has a schematic for the circuit used. It is actually an egg timer running on a 16C54. With some modification you could probably make it do what you want. Its on page 2-103 and listed as AN615. Shawn {Original Message removed}

If your looking for an IC to do the job both Xicor and Philips do a nice little 8-DIP (& SOIC) package, Xicor XC1202, or the Philips PCF8563. Hop this helps Andy -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

My Int routine looks like this: ORG 0x0004 btfsc INTCON,T0IF goto timer0_int goto end_int timer0_int movlw 0 movwf TMR0 bcf INTCON,T0IF goto end_int asdaa nop goto asdaa end_int retfie Somehow the T0IF doesn't get cleared.... whats wrong??? regards, BEN -------------------------- Benjamin Menküc Auto-Intern GmbH Haberlandstr. 125 44359 Dortmund Tel: 0231-1893070 Fax: 0231-93699548 http://www.auto-intern.com Meinen PGP-Schlüssel kann man unter: http://www.auto-intern.com/php/pgp_menkuec.php finden. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

Either (a) Your interrupt happens while you are in another bank or (b) Your PIC is broken. /\/\/\/*=Martin {Original Message removed}

but it goes already to timer0_int so the bank should be right.... And i am pretty sure that my pic is not broken.. However i am doing isp debuggin... might that be the reason? {Original Message removed}

I was wrong, since INTCON is mapped to all the banks. Maybe you are right. If you are debugging slowly the timer may overflow again after you clear TOIF. Did you try simulating it in MPLAB? Put a breakpoint in the interrupt code and step through it. /\/\/\/*=Martin {Original Message removed}

Benjamin Menküc wrote: > > but it goes already to timer0_int so the bank should be right.... And i am > pretty sure that my pic is not broken.. However i am doing isp debuggin... > might that be the reason? I just simulated that code with this simple program and it works ok, so perhaps you have the WDT enabled, or something is wrong in the main loop. list P = 16F84 #include "p16f84.inc" ORG 0h goto start ORG 0x0004 btfsc INTCON,T0IF goto timer0_int goto end_int timer0_int movlw 0 movwf TMR0 bcf INTCON,T0IF goto end_int asdaa nop goto asdaa end_int retfie start bsf STATUS,RP0 ; prescale = 1:2 clrf OPTION_REG bcf STATUS,RP0 clrf INTCON bsf INTCON,T0IE ; enable TMR0 IRQ bsf INTCON,GIE Loop nop nop goto Loop end -- Best regards Tony mICros http://www.bubblesoftonline.com .....salesKILLspam@spam@bubblesoftonline.com -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

Be careful, you interrupt service routine is rather dangerous: 1: you are not saving an registers (should save at least STATUS and W). 2: you are not ensuring correct bank on entry. As written, this handler will zero W as seen by non-interupt code. Bob Ammerman RAm Systems {Original Message removed}

I don't see why are needed here 1 and 2, the tmr0 always is rollowing from 255 to 0 at every intcon_t0if events. Also clearing intcon_t0if have nothing to do with t0ie or gie. You may use intcon_t0if without enabling any interrupts in the main program. regards, Vasile timer0_int 1 movlw 0 2 movwf TMR0 > bcf INTCON,T0IF > goto end_int On Thu, 14 Feb 2002, Tony Nixon wrote: {Quote hidden}> Benjamin Menküc wrote: > > > > but it goes already to timer0_int so the bank should be right.... And i am > > pretty sure that my pic is not broken.. However i am doing isp debuggin... > > might that be the reason? > > I just simulated that code with this simple program and it works ok, so > perhaps you have the WDT enabled, or something is wrong in the main > loop. > > > list P = 16F84 > > #include "p16f84.inc" > > ORG 0h > goto start > > ORG 0x0004 > > btfsc INTCON,T0IF > goto timer0_int > goto end_int > timer0_int > movlw 0 > movwf TMR0 > bcf INTCON,T0IF > goto end_int > asdaa > nop > goto asdaa > end_int > retfie > > > start bsf STATUS,RP0 ; prescale = 1:2 > clrf OPTION_REG > bcf STATUS,RP0 > clrf INTCON > bsf INTCON,T0IE ; enable TMR0 IRQ > bsf INTCON,GIE > > Loop nop > nop > goto Loop > > end > > > -- > Best regards > > Tony > > mICros > http://www.bubblesoftonline.com > salesKILLspambubblesoftonline.com > > -- > http://www.piclist.com hint: The PICList is archived three different > ways. See http://www.piclist.com/#archives for details. > > -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email .....listservKILLspam.....mitvma.mit.edu with SET PICList DIGEST in the body