USART interrupt not interrupting right

[Morpheus]

Hi All!

I'm working with a 16f628A

I wrote a "simple" code, the interrupt has just to turn on a led when a 9-bit char with the 9th bit enabled is received on the usart rx port.

the main program just make blinking a led.
the results are that if I receive an address(8 bit char with the 9th bit set), the blinking led remains on(or off) doubling the time(2 secs instead 1), and the led that the interrupt had to turn on, remains off.

I'll post my code.

CODE:
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INCLUDE "MODEDEFS.BAS"

TRISA=%11110000
TRISB=%00000010

cmcon=7 ' predispone la portaA come I/O digitali


'INTCON ( Interruption Control register )
intcon.7=1 'GIE : Global Interrupt Enable bit
intcon.6=1 'PEIE : Peripheral Interrupt Enable bit ( This bit should be set when using the CCP interruption so on )
intcon.5=0 'T0IE : TMR0 Overflow Interrupt Enable bit
intcon.4=0 'INTE : RB0/INT Interrupt Enable bit
intcon.3=0 'RBIE : RB Port Change Interrupt Enable bit
intcon.2=0 'T0IF : TMR0 Overflow Interrupt Flag bit
intcon.1=0 'INTF : RB0/INT Interrupt Flag bit
intcon.0=0 'RBIF : RB Port Change Interrupt Flag bit

'definisco il registro di ricezione RCSTA
rcsta.7=1 'SPEN serial port enable bit
rcsta.6=1 'RX9 9-bit receive enable bit
rcsta.5=0 'SREN single receive enable bit
rcsta.4=1 'CREN continous receive enable bit
rcsta.3=1 'ADDEN address detect enable bit
rcsta.2=0 'FERR framing error bit(read only)
rcsta.1=0 'OERR overrun error bit(read only)
rcsta.0=0 'RX9D 9th bit of receive data (read only)


'definisco il registro di trasmissione TXSTA
txsta.7=0 'CSRC : Clock Source Select bit
txsta.6=0 'TX9 : 9-bit Transmit Enable bit
txsta.5=1 'TXEN : Transmit Enable bit
txsta.4=0 'SYNC : USART Mode Select bit 0=asincrono
txsta.3=0 ' N/A
txsta.2=1 'BRGH : High Baud Rate Select bit
txsta.1=0 'TRMT : Transmit Shift Register Status bit ( Read only )
txsta.0=0 'TX9D : 9th bit of transmit data. Can be parity bit.


'PIE1 ( Peripheral Interrupt Enable register ) 8Ch
PIE1.7=0 'EEIE : EE Write Complete Interrupt Enable Bit
PIE1.6=0 'CMIE : Comparator Interrupt Enable bit
PIE1.5=1 'RCIE : USART Receive Interrupt Enable bit
PIE1.4=0 'TXIE : USART Transmit Interrupt Enable bit
PIE1.3=0 ' N/A
PIE1.2=0 'CCP1IE : CCP1 Interrupt Enable bit
PIE1.1=0 'TMR2IE : TMR2 to PR2 Match Interrupt Enable bit
PIE1.0=0 'TMR1IE : TMR1 Overflow Interrupt Enable bit


'azzera tutti i flag di interrupt
PIR1.7=0
PIR1.6=0
PIR1.5=0 'azzera l'RCIF
PIR1.4=0
PIR1.3=0
PIR1.2=0
PIR1.1=0
PIR1.0=0



'DEFINE HSER_BAUD 38400 ' Set baud rate
'DEFINE HSER_SPBRG 15 ' Set SPBRG directly (normally set by HSER_BAUD)

'setta la velocità a 38800
SPBRG.7=0
SPBRG.6=0
SPBRG.5=0
SPBRG.4=0
SPBRG.3=1
SPBRG.2=1
SPBRG.1=1
SPBRG.0=1



DEFINE OSC 10




Enable interrupt


i VAR WORD
led VAR BIT
led2 VAR BIT
ric VAR BYTE



on interrupt GoTo indirizzo

GoTo ricevi


indirizzo:

' HSerin [ric]'riceve un carattere da seriale
' IF led2=1 Then
' PORTA.0=0:led2=0
' Else
' PORTA.0=1:led2=1
' EndIF
PORTB.7=1

Resume


ricevi:

For i=1 to 65000
Next

IF led=1 Then
PORTB.6=0:led=0
Else
PORTB.6=1:led=1
EndIF
GoTo ricevi

-------------------------------------------------------------------
/CODE


I hope someone can help me..
Thanks,
Simone
P.S. Sorry for my english!