How On Interrupt works?

[koossa]

Here is my new code, but still the RX LED does not work.

<hr>
<b>Code for TX</b>
<hr>
<code>
&nbsp;&nbsp;Include "Modedefs.bas"

&nbsp;&nbsp;DEFINE&nbsp;&nbsp;&nbsp;&nbsp; OSC 4

&nbsp;&nbsp;DE_OR_RE&nbsp;&nbsp;&nbsp;&nbsp;VAR PORTC.5&nbsp;&nbsp;&nbsp;&nbsp; ' DE and RE Pin of SN75176
&nbsp;&nbsp;LEDPIN&nbsp;&nbsp;&nbsp;&nbsp; VAR PORTD.2&nbsp;&nbsp;&nbsp;&nbsp; ' LED to confirm PIC is running
&nbsp;&nbsp;DATARECEIVED&nbsp;&nbsp;VAR BYTE
&nbsp;&nbsp;
&nbsp;&nbsp;'======== HSEROUT, HSERIN SETTINGS ==========
&nbsp;&nbsp;DEFINE HSER_RCSTA 90h
&nbsp;&nbsp;DEFINE HSER_TXSTA 24h
&nbsp;&nbsp;DEFINE HSER_BAUD 9600

&nbsp;&nbsp;ADCON1 = 7

&nbsp;&nbsp;RCIF&nbsp;&nbsp;VAR&nbsp;&nbsp;PIR1.5& nbsp;&nbsp;&nbsp;&nbsp;' Alias RCIF (USART Receive Interrupt Flag)
&nbsp;&nbsp;OERR&nbsp;&nbsp;VAR&nbsp;&nbsp;RCSTA.1 &nbsp;&nbsp;&nbsp;&nbsp;' Alias OERR (USART Overrun Error Flag)
&nbsp;&nbsp;CREN&nbsp;&nbsp;VAR&nbsp;&nbsp;RCSTA.4 &nbsp;&nbsp;&nbsp;&nbsp;' Alias CREN (USART Continuous Receive Enable)
&nbsp;&nbsp;
Main:
&nbsp;&nbsp;HIGH DE_OR_RE&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ' Make ready for RX
&nbsp;&nbsp;HSEROUT ["1"]&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&n bsp;&nbsp;&nbsp;&nbsp; ' Send R1
&nbsp;&nbsp;HIGH LEDPIN
&nbsp;&nbsp;PAUSE 5000
&nbsp;&nbsp;LOW LEDPIN
&nbsp;&nbsp;PAUSE 5000
GOTO MAIN

END
</code>


<hr>
<b>Code for RX</b>
<hr>
<code>
&nbsp;&nbsp;Include "Modedefs.bas"
&nbsp;&nbsp;&nbsp;&nbsp;
&nbsp;&nbsp;DEFINE&nbsp;&nbsp;&nbsp;&nbsp; OSC 4

&nbsp;&nbsp;DE_OR_RE&nbsp;&nbsp;&nbsp;&nbsp;VAR PORTC.5&nbsp;&nbsp;&nbsp;&nbsp; ' DE and RE Pin of SN75176 (RS485)
&nbsp;&nbsp;LEDPIN&nbsp;&nbsp;&nbsp;&nbsp; VAR PORTD.2&nbsp;&nbsp;&nbsp;&nbsp; ' LED Pin
&nbsp;&nbsp;i&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbs p; VAR BYTE
&nbsp;&nbsp;DATARECEIVED&nbsp;&nbsp;VAR BYTE

&nbsp;&nbsp;'======== HSEROUT, HSERIN SETTINGS ==========&nbsp;&nbsp;
&nbsp;&nbsp;DEFINE HSER_RCSTA 90h
&nbsp;&nbsp;DEFINE HSER_TXSTA 24h
&nbsp;&nbsp;DEFINE HSER_BAUD 9600

&nbsp;&nbsp;ADCON1 = 7

&nbsp;&nbsp;RCIF&nbsp;&nbsp;VAR&nbsp;&nbsp;PIR1.5& nbsp;&nbsp;&nbsp;&nbsp;' Alias RCIF (USART Receive Interrupt Flag)
&nbsp;&nbsp;OERR&nbsp;&nbsp;VAR&nbsp;&nbsp;RCSTA.1 &nbsp;&nbsp;&nbsp;&nbsp;' Alias OERR (USART Overrun Error Flag)
&nbsp;&nbsp;CREN&nbsp;&nbsp;VAR&nbsp;&nbsp;RCSTA.4 &nbsp;&nbsp;&nbsp;&nbsp;' Alias CREN (USART Continuous Receive Enable)

&nbsp;&nbsp;LOW DE_OR_RE&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&n bsp;&nbsp;&nbsp;' Make ready for RX
&nbsp;&nbsp;INTCON = %11000000&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp ;&nbsp;&nbsp;&nbsp; ' Enable interrupts
&nbsp;&nbsp;ON INTERRUPT GoTo SerialDataReceived ' Declare interrupt handler routine
&nbsp;&nbsp;PIE1.5 = 1&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;& nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ' Enable interrupt on USART

DoSomeStuff:
&nbsp;&nbsp;For i = 0 to 10
&nbsp;&nbsp;&nbsp;&nbsp;Pause 2
&nbsp;&nbsp;Next i
&nbsp;&nbsp;GOTO DoSomeStuff


&nbsp;&nbsp;DISABLE&nbsp;&nbsp;
SerialDataReceived:&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;& nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb sp;&nbsp;&nbsp;' Buffer the character received
&nbsp;&nbsp;HSerin [DATARECEIVED]&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp ;' Read USART and store character to next empty location
&nbsp;&nbsp;GOSUB BLINK
&nbsp;&nbsp;IF RCIF Then SerialDataReceived
&nbsp;&nbsp;RESUME
&nbsp;&nbsp;ENABLE
&nbsp;&nbsp;
&nbsp;&nbsp;
BLINK:
&nbsp;&nbsp;HIGH LEDPIN
&nbsp;&nbsp;PAUSE 1000
&nbsp;&nbsp;LOW LEDPIN
&nbsp;&nbsp;PAUSE 1000
&nbsp;&nbsp;RETURN

END
</code>

[Bruce]

Information on INTCON will be found in the PIC data sheet. Not your PBP manual.

Do NOT GOSUB to another routine outside the DISABLE / ENABLE block in your interrupt handler.

After the ENABLE, PBP begins placing more code to jump to the interrupt check routine. So what happens is you jump out to BLINK, you land smack on code that sees the interrupt has not been serviced, and bingo, you're sent right back to SerialDataReceived before code in the BLINK routine can execute.

Keep all code in your interrupt handler in the protected area between the DISABLE/ENABLE block, or simply remove ENABLE. If SerialDataReceived and BLINK are the last routines in program memory, then you don't even need the ENABLE. This tells PBP to start inserting code before & after each PBP statement to test for the interrupt condition.

Try this;

 DISABLE  
SerialDataReceived:                ' Buffer the character received
  HSerin [DATARECEIVED]        ' Read USART and store character to next empty location
  IF RCIF Then SerialDataReceived
  HIGH LEDPIN
  PAUSE 1000
  LOW LEDPIN
  PAUSE 1000
  RESUME

  END

[koossa]

Thank you very much Bruce!!!

[koossa]

It is working now!!!
Thank you very much for your help Bruce!!!!