TMR1 external LP xtal setup check

can someone double check my setup for TMR1 to use 32KHz external LP xtal on 16F877a?

I think i got it right, but TMR1 doesn't seem to be working...

Code:

TMR1L = 0 ' reset TMR1 low to 0 TMR1H = 0 ' reset TMR1 high to 0 PIE1.0 = 0 ' Disable TMR1 interupt (double check) T1CON.5 = 0 ' Setup TMR1 timings 1:1 T1CON.4 = 0 ' Setup TMR1 timings 1:1 T1CON.3 = 1 ' Oscillator is ON (LP OSC Mode) T1CON.2 = 1 ' do not Synchronize external clock input T1CON.1 = 1 ' External clock from pin RC0 T1CON.0 = 1 ' Enables Timer1

thanks

Yes, that should make Timer1 keep time with a watch crystal.
Assuming 100 other things are correct ...

Code:

T1CON.5 = 0 ' Setup TMR1 timings 1:1 T1CON.4 = 0 ' Setup TMR1 timings 1:1 T1CON.3 = 1 ' Oscillator is ON (LP OSC Mode) T1CON.2 = 1 ' do not Synchronize external clock input T1CON.1 = 1 ' External clock from pin RC0 T1CON.0 = 1 ' Enables Timer1

Of course, the timer will only tick every 2 seconds, unless you reload the timer each time it overflows.

You've added capacitors to the crystal right? ...
You're responding to the overflow flag? ...
The TMR1IE enable bit isn't set? ...
I'm guessing without the program again ...
<br>

Thanks darrel,

i've got a weird one here... i'm not sure what the hell is going on but something is screwed...

basically, it's a test program, every time TMR1 over flows it toggles an LED, just so that i can see it's working...

it's doing weird things to the ports so i simulated it in oshonsoft's pic simulator...
i toggle the PIR1.0 manually...
What i found is the first overrflow turns PORTB.1 on,
Second overflow turns PORTB.3 on
3 and above overflows turn PORTC3 on and off...

It's not supposed to touch PORTC at all!

Here is that BAS file

Code:

ASM device pic16F877A device HS_OSC device WDT_ON device PWRT_ON device BOD_ON device LVP_OFF device WRT_OFF device CPD_OFF device DEBUG_OFF ENDASM Define OSC 24 ' Set clock speed INTCON = 0 ' Disable all interupts TRISE = %00000111 ' Set PortE to all inputs TRISD = %00000000 ' Set PortD to all outputs TRISC = %00000000 ' Set PortC to all outputs TRISB = %00000000 ' Set PortB to all outputs TRISA = %11111111 ' Set PORTA to all input HIGH PORTB HIGH PORTB.0 'pause 5000 low PORTB gosub TMR1setup loop: if PIR1.0 = 1 then ' if TMR1 has overflowed T1CON.0 = 0 ' Stop tmr 1 PIR1.0 = 0 toggle PORTB gosub TMR1setup ' reset and restart TMR1 endif goto loop TMR1setup: TMR1L = 0 ' reset TMR1 low to 0 TMR1H = 0 ' reset TMR1 high to 0 PIE1.0 = 0 ' Disable TMR1 interupt (double check) T1CON.5 = 0 ' Setup TMR1 timings 1:1 T1CON.4 = 0 ' Setup TMR1 timings 1:1 T1CON.3 = 1 ' Oscillator is ON (LP OSC Mode) T1CON.2 = 1 ' do not Synchronize external clock input T1CON.1 = 1 ' External clock from pin RC0 T1CON.0 = 1 ' Enables Timer1 return

Here is the ASM file

Code:

; PicBasic Pro Compiler 2.44, (c) 1998, 2003 microEngineering Labs, Inc. All Rights Reserved. PM_USED EQU 1 INCLUDE "16F877A.INC" ; Define statements. #define CODE_SIZE 8 #define OSC 24 RAM_START EQU 00020h RAM_END EQU 001EFh RAM_BANKS EQU 00004h BANK0_START EQU 00020h BANK0_END EQU 0007Fh BANK1_START EQU 000A0h BANK1_END EQU 000EFh BANK2_START EQU 00110h BANK2_END EQU 0016Fh BANK3_START EQU 00190h BANK3_END EQU 001EFh EEPROM_START EQU 02100h EEPROM_END EQU 021FFh R0 EQU RAM_START + 000h R1 EQU RAM_START + 002h R2 EQU RAM_START + 004h R3 EQU RAM_START + 006h R4 EQU RAM_START + 008h R5 EQU RAM_START + 00Ah R6 EQU RAM_START + 00Ch R7 EQU RAM_START + 00Eh R8 EQU RAM_START + 010h FLAGS EQU RAM_START + 012h GOP EQU RAM_START + 013h RM1 EQU RAM_START + 014h RM2 EQU RAM_START + 015h RR1 EQU RAM_START + 016h RR2 EQU RAM_START + 017h _PORTL EQU PORTB _PORTH EQU PORTC _TRISL EQU TRISB _TRISH EQU TRISC #define _PORTB_0 PORTB, 000h #define _PIR1_0 PIR1, 000h #define _T1CON_0 T1CON, 000h #define _PIE1_0 PIE1, 000h #define _T1CON_5 T1CON, 005h #define _T1CON_4 T1CON, 004h #define _T1CON_3 T1CON, 003h #define _T1CON_2 T1CON, 002h #define _T1CON_1 T1CON, 001h INCLUDE "XTALTE~1.MAC" INCLUDE "PBPPIC14.LIB" ASM? device pic16F877A device HS_OSC device WDT_ON device PWRT_ON device BOD_ON device LVP_OFF device WRT_OFF device CPD_OFF device DEBUG_OFF ENDASM? MOVE?CB 000h, INTCON MOVE?CB 007h, TRISE MOVE?CB 000h, TRISD MOVE?CB 000h, TRISC MOVE?CB 000h, TRISB MOVE?CB 0FFh, TRISA HIGH?B PORTB HIGH?T _PORTB_0 LOW?B PORTB GOSUB?L _TMR1setup LABEL?L _loop CMPNE?TCL _PIR1_0, 001h, L00001 MOVE?CT 000h, _T1CON_0 MOVE?CT 000h, _PIR1_0 TOGGLE?B PORTB GOSUB?L _TMR1setup LABEL?L L00001 GOTO?L _loop LABEL?L _TMR1setup MOVE?CB 000h, TMR1L MOVE?CB 000h, TMR1H MOVE?CT 000h, _PIE1_0 MOVE?CT 000h, _T1CON_5 MOVE?CT 000h, _T1CON_4 MOVE?CT 001h, _T1CON_3 MOVE?CT 001h, _T1CON_2 MOVE?CT 001h, _T1CON_1 MOVE?CT 001h, _T1CON_0 RETURN? END

And here is the MAC file...

Code:

NOLIST ; PicBasic Pro Compiler 2.44, (c) 1998, 2003 microEngineering Labs, Inc. All Rights Reserved. LABEL?L macro Label RST?RP ifdef PM_USED LALL Label XALL else Label endif endm CMPNE?TCL macro Regin, Bitin, Cin, Label if (Cin == 0) CLRWDT? BIT?GOTO 1, Regin, Bitin, Label else if (Cin == 1) CLRWDT? BIT?GOTO 0, Regin, Bitin, Label else L?GOTO Label endif endif endm ASM? macro RST?RP endm ENDASM? macro endm GOSUB?L macro Label local dlabel ifdef DEBUG_STACK CHK?RP DEBUG_STACK ifdef DEBUG_STACK_ADDR bcf STATUS, C rlf DEBUG_STACK, W addlw DEBUG_STACK_ADDR movwf FSR movlw low (dlabel) movwf INDF incf FSR, F movlw (dlabel) >> 8 movwf INDF endif incf DEBUG_STACK, F endif L?CALL Label dlabel endm GOTO?L macro Label L?GOTO Label endm HIGH?B macro Bin MOVE?BA Bin L?CALL HIGHP endm HIGH_USED = 1 HIGH?T macro Regin, Bitin MOVE?CT 1, Regin, Bitin MOVE?CT 0, ((Regin) + 80h), Bitin endm LOW?B macro Bin MOVE?BA Bin L?CALL LOWP endm LOW_USED = 1 RETURN? macro ifdef DEBUG_STACK CHK?RP DEBUG_STACK decf DEBUG_STACK, F endif RST?RP return endm TOGGLE?B macro Bin MOVE?BA Bin L?CALL TOGGLE endm TOGGLE_USED = 1 LIST

And this is the HEX file

Code:

:1000000026280F2080040B280F20FF3A80050C289B :100010000F2080060B28FF3A841780052128A800AE :100020000630A8190730840000308A0028080739F4 :10003000820701340234043408341034203440344C :100040008034831303138312640008008B0183162A :1000500007308900880187018601FF3085008312FF :1000600006088A010120061483160610831206086A :100070008A0104208A110A124C2064008A110A1293 :100080000C1C4A2810100C1006088A0108208A113E :100090000A124C208A013D288E018F0183160C1014 :1000A000831290121012901510159014101408005D :02400E00763FFB :00000001FF

I'm struggling to see whats gone wrong...

Code:

HIGH PORTB TOGGLE PORTB

What those do is read PORTB, takes the value and turns it into a pin number, then toggles that pin.

As the value of the PORT changes, so does the PIN that's being toggled.
<br>

indeed... i replaced portb with portb.0 and it now seems to work...

I used a stopwatch to time the LED and it was slightly over... I timed it 10 times and each one came back within 0.1 second of the same value so i've worked out a preload for TMR1...

I'm going to have a play with your (DT's) instant interupts, i need to use interupts now coz i'm dealing with HS serial coms...

Thanks Darrel