'----------------------------------------------- 
' DEMONSTARTION OF A 100THS OF A SECOND TIMER 
' COUNTING UP TO 255 DAYS 
' 
' 
' FIDDLE WITH FUDGE FACTOR TO IMPROVE ACCURACY 
' 
' BY TIM BOX NOV 03 
'----------------------------------------------- 

DEVICE 16F628

	REMARKS ON
	
	REMINDERS OFF
	CONFIG HS_OSC,PWRTE_ON,CP_OFF,WDT_OFF,LVP_OFF,MCLRE_OFF,BODEN_ON
	REMINDERS ON

	ON_INTERRUPT Horloge
	
	ALL_DIGITAL ON

	DECLARE XTAL=20

	DECLARE LCD_INTERFACE 4
	DECLARE LCD_LINES 2
	DECLARE LCD_DTPIN PORTB.0
	DECLARE LCD_ENPIN PORTA.4
	DECLARE LCD_RSPIN PORTA.3
	
	SYMBOL GIE  = INTCON.7
	
	SYMBOL T0IF   = INTCON.2
	SYMBOL T0IE   = INTCON.5
	SYMBOL TMR1IF = PIR1.0
	SYMBOL TMR1IE = PIE1.0
	SYMBOL TMR2IF = PIR1.1
	SYMBOL TMR2IE = PIE1.1
	
	SYMBOL PS0 = OPTION_REG.0
	SYMBOL PS1 = OPTION_REG.1
	SYMBOL PS2 = OPTION_REG.2
	SYMBOL PSA = OPTION_REG.3
	SYMBOL T0SE= OPTION_REG.4
	SYMBOL T0CS= OPTION_REG.5
	
	SYMBOL T1CKPS0 = T1CON.4
	SYMBOL T1CKPS1 = T1CON.5
	SYMBOL T1OSCEN = T1CON.3
	SYMBOL T1SYNC  = T1CON.2
	SYMBOL TMR1CS  = T1CON.1
	SYMBOL TMR1ON  = T1CON.0
	
	SYMBOL TOUTPS3 = T2CON.6
	SYMBOL TOUTPS2 = T2CON.5
	SYMBOL TOUTPS1 = T2CON.4
	SYMBOL TOUTPS0 = T2CON.3
	SYMBOL TMR2ON  = T2CON.2
	SYMBOL T2CKPS1 = T2CON.1
	SYMBOL T2CKPS0 = T2CON.0

DIM _100THS ' DECLARE ALL VARS AS BYTES 
DIM SECS 
DIM MINS 
DIM HOURS 
DIM DAYS 
DIM TEMP_100THS 
DIM TEMP_SECS 
DIM TEMP_MINS 
DIM TEMP_HOURS 
DIM TEMP_DAYS 



DIM TIMER1REG AS TMR1L.WORD ' MAKE THE TIMER VAR INTO A WORD 
SYMBOL FUDGE_FACTOR = 7 ' FIDDLE WITH TO IMPROVE ACCURACY 
SYMBOL TMR1_VAL =((65536)-(XTAL*2500))+FUDGE_FACTOR ' CALCULATE OSC OFFSET VALUES FOR 100HZ INTERRUPT 

ON_INTERRUPT INTERRUPT_ROUTINE ' WHERE TO GO ON AN INTERRUPT 


GOTO START ' JUMP THE INTERRUPT CODE 

INTERRUPT_ROUTINE: 

CLEAR T1CON.0 ' STOP TMR1 
TIMER1REG = TIMER1REG + TMR1_VAL ' LOAD TMR1 
SET T1CON.0 ' START TMR1 

INC _100THS 
IF _100THS = 100 THEN ' UP 100TS 
CLEAR _100THS 
INC SECS ' UP SECONDS 
IF SECS = 60 THEN 
CLEAR SECS 
INC MINS ' UP MINS 
IF MINS = 60 THEN 
CLEAR MINS 
INC HOURS 
IF HOURS = 24 THEN ' UP HOURS 
CLEAR HOURS 
INC DAYS 
ENDIF 
ENDIF 
ENDIF 
ENDIF 
CLEAR PIR1.0 ' CLEAR TMR1 INTERRUPT FLAG 
CONTEXT RESTORE ' END INTERRUPT ROUTINE 

START: 
CLEAR ' CLEAR ALL VARS 
T1CON = %00000000 ' SET UP TMR1 TO HAVE 1:1 PRESCALER AND ACT AS A TIMER 
PIR1.0 = 0 ' CLEAR TMR1 INTERRUPT FLAG 
INTCON = %11000000 ' GLOBAL AND PERIPHERAL INTERRUPTS ON 
PIE1.0 = 1 ' ENABLE TMR1 AS PERIPHERAL INTERRUPT SOURCE 
T1CON.0 = 1 ' SET TIMER1 RUNNING 

CLS ' CLEAR THE LCD 

WHILE 1 = 1 ' MAKE AN ENDLESS LOOP 
GIE = 0 ' TURN OFF GLOBAL INTERRUPTS 
WHILE GIE = 1 : GIE = 0 : WEND ' AND MAKE SURE THEY ARE OFF 
TEMP_100THS = _100THS ' MAKE A COPY OF THE VARS 
TEMP_SECS = SECS 
TEMP_MINS = MINS 
TEMP_HOURS = HOURS 
TEMP_DAYS = DAYS 
GIE = 1 ' TURN THE INTERRUPTS BACK ON 

PRINT AT 1,1,DEC2 TEMP_DAYS,":",DEC2 TEMP_HOURS,":",DEC2 TEMP_MINS,":",DEC2 TEMP_SECS,":",DEC2 TEMP_100THS 

DELAYMS 100 ' SMALL DELAU 

WEND ' ROUND AND ROUND WE GO 

STOP