I've set this code to work from 87 to 108 MHz......but I have problem:

When I press UP it goes ok from 87,0 87,1 87,2 87,3 87,4 87,5 87,6 87,7 and thjen jumps directly to 88?????? And whole time like this on whole band to 108MHz, up or down....

everytim it steps ok from 100,0 to 100, 7 with step of 0,1 and then after 100,7 directly step to 101,0......I don't know why jumps over 100,8 100,9????? This is on whole band I just took 100 as example.


this i the code:

Code:
   
DEFINE LCD_DREG PORTD
DEFINE LCD_DBIT 4
DEFINE LCD_RSREG PORTD
DEFINE LCD_RSBIT 1
DEFINE LCD_EREG PORTD
DEFINE LCD_EBIT 0
DEFINE LCD_BITS 4
DEFINE LCD_LINES 2
DEFINE LCD_COMMANDUS 2000
DEFINE LCD_DATAUS 50



DEFINE I2C_SCLOUT 1
	


' definition I2C communication
	SCL   	var     	PORTB.1        	 ' SCL on RB1  
	SDA	    var     	PORTB.0	      	 ' SDA on RB0 

'press:
	MEMO	var	PORTB.3		' 
	UP   	var	PORTB.4		' press for FREQ UP RB.4
	DOWN	var	PORTB.5		' press for FREQ DOWN RB.5


	
	INPUT	UP			'Up et Down sont des entrées
	INPUT	DOWN
	INPUT	MEMO



   
   
    'Fmin =88 MHz, F max= 108 MHz 
' ** DECLARATION OF THE VARIABLES

b1 var BYTE
b2 var BYTE
b3 var BYTE
b5 var BYTE

F1 var WORD
F2 var WORD
F3 var WORD


ADDR1        VAR BYTE
TMP          VAR WORD
TMP_LO       VAR TMP.LOWBYTE
TMP_HI       VAR TMP.HIGHBYTE
PLLBASE      VAR WORD
PLL          VAR WORD
LO           VAR PLL.LOWBYTE
HI           VAR PLL.HIGHBYTE
PAS          VAR BYTE '1=125kHz, 2=250kHz, 4=500kHz, 8=1MHz 

'*** INITIAL DATA *** 

ADDR1=$C2 'adress I2C of SDA5055 (ADDR1=$C0 , adress I2C of TSA5511)
PLLBASE=696  'beginning with 87 MHz : 87 / 0,125 = 696
PAS = 1 'step of 0.1 MHZ by default    ?????
PAUSE 100
LCDOUT $FE, 1 ' Clear LCD screen
LCDOUT " PLL FM 88-108" ' post text during 1 second
LCDOUT $FE,$C0 
LCDOUT " BT-20" 
PAUSE 1000 

EEPROM 0,[$90,$01] 'initial data TMP = PLLBASE  corresponds to F = 88 MHz


'The starting point is 88 MHz given by PLLBASE. One adds a shift of 125kHz * TMP
'TMP is on 16 bits, therefore 65535 possible frequencies.
' 
'*** READING OF THE DECALAGE TMP ***

READ 0,TMP_LO 'reads the 8 bits of weak weight
READ 1,TMP_HI 'reads the 8 bits of strong weight


' *** BEGINNING OF THE PROGRAM***

MAIN: 
PLL = PLLBASE + TMP

I2CWRITE SDA,SCL,ADDR1,[HI,LO,$8E] 'Sending of the data to the module 

GOSUB CALCUL 'calculate the frequency for posting
GOSUB AFFICHAGE 'post the frequency
PAUSE 500


'*** press routine ***

BOUCLE: 
BUTTON UP,0,10,2,b1,1,MONTE 'supervise the button UP
BUTTON DOWN,0,10,2,b2,1,DESCEND 'supervise the button DOWN
BUTTON MEMO,0,255,0,b5,1,STORE 'supervise the button MEMO
' only step size of 125KHz is handled
' BUTTON CH_PAS,1,255,0,b3,1, CHOIX 'supervise the button PAS 
PAUSE 100 'pauses of 0.1s
GOTO BOUCLE


MONTE: '** INCREASE THE FREQUENCY OF 1 PAS (STEP)

TMP = TMP + PAS
IF TMP > 168 THEN TMP = 0 'Fmax = 108 MHz  ---> (Fmax - Fmin) / 0,125   -> (108-87)/0,125  = 168
GOTO MAIN

DESCEND: '** DECREASE THE FREQUENCY OF 1 PAS (STEP)

IF TMP = 0 THEN TOP
TMP = TMP - PAS
GOTO MAIN

TOP: TMP=168   ' max reading in Tmp
GOTO MAIN

RAZ_TMP: TMP = 0
GOTO MAIN

CHOIX: '** CHOICE OF THE PAS (STEP) 

IF PAS = 8 THEN SAUTE
PAS = PAS*2

GOSUB AFFICHAGE 'post the frequency
GOTO BOUCLE

SAUTE: PAS = 1

GOTO BOUCLE

CALCUL: ' ** CALCULATION OF THE FREQUENCY

F1 = PLL 'cut off 1GHz 
F2 = F1/8 'give them MHz
F3 = 100*(F1//8) 'give them kHz        ?????
RETURN

AFFICHAGE: 
LCDOUT $FE, 1 'Clear LCD screen 
'LCDOUT #1 'post the 1 of Giga we don't need this because we only have 100 of MHz!!!
LCDOUT #F2 'post the other digits 
LCDOUT "." 'post the comma
LCDOUT #F3 'post the Khz
LCDOUT " MHz "

STORE:				
		WRITE 0, TMP_LO		
		WRITE 1, TMP_HI		
		GOTO BOUCLE