Playing with Interrupts

[tacbanon]

Hi everyone, I'm trying to understand the following code that triggers an interrupt when data received on PortC.7. I tried to modify it and incorporate USB CDC to send back the received data to pc.

asm
    __CONFIG    _CONFIG1L, _PLLDIV_5_1L & _CPUDIV_OSC1_PLL2_1L & _USBDIV_2_1L
    __CONFIG    _CONFIG1H, _FOSC_HSPLL_HS_1H & _FCMEN_OFF_1H & _IESO_OFF_1H
    __CONFIG    _CONFIG2L, _PWRT_ON_2L & _BOR_ON_2L  & _BORV_2_2L  & _VREGEN_ON_2L   
    __CONFIG    _CONFIG2H, _WDT_OFF_2H 
    __CONFIG    _CONFIG3H, _MCLRE_ON_3H & _LPT1OSC_OFF_3H & _PBADEN_OFF_3H & _CCP2MX_ON_3H 
    __CONFIG    _CONFIG4L, _STVREN_ON_4L & _LVP_OFF_4L & _ICPRT_OFF_4L  & _XINST_OFF_4L & _DEBUG_OFF_4L 
endasm
DEFINE LCD_DREG PORTB
DEFINE LCD_DBIT 0
DEFINE LCD_EREG PORTB
DEFINE LCD_EBIT 5
DEFINE LCD_RSREG PORTB
DEFINE LCD_RSBIT 4
DEFINE LCD_BITS 4
DEFINE LCD_LINES 2
DEFINE LCD_COMMANDUS 2000
DEFINE LCD_DATAUS 50


       
        DEFINE OSC 48
        DEFINE HSER_RCSTA 90h ' enable serial port, 
        define HSER_TXSTA 24h ' enable transmit, 
        define HSER_SPBRG 25 ' set baudrate to 9600                   
        DEFINE HSER_CLOERR  1 ' automatic clear overrun error  
        
        TRISC  = %10000000    ' PORTC.7 is the RX input, PORTC.6 is the TX output
                              
    
    '   Serial communication definition
    '   ===============================
        '
ADCON1 = %00001111      'Set up ADCON1 register no matter what you're doing!!!!!!
'::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
INCLUDE "cdc_desc.bas" 'Descriptor file    for CDC    serial demo
INCLUDE "MODEDEFS.BAS"       ' Include Shiftin/out modes
INCLUDE "DT_INTS-18.bas"     ' Base Interrupt System
INCLUDE "ReEnterPBP-18.bas"  ' Include if using PBP interrupts
'::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
    '   Variable definition
'::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
        
RCIF       VAR     PIR1.5     ' Receive  interrupt flag (1=full , 0=empty)
TXIF       VAR     PIR1.4     ' Transmit interrupt flag (1=empty, 0=full)
TRISC = %10000000
PortC = %00000000    
led        var     PORTC.0
led1       var     PORTC.1
led2       var     PORTC.2
holdoff    var     word
SerialData var     byte[15]
DataRec    var     byte[15]
buffer     var     byte[20]
flag1      var     byte
flag1 = 0
cnt        var     byte
cnt = 5 
ASM
INT_LIST  macro    ; IntSource,        Label,  Type, ResetFlag?
        INT_Handler   RX_INT,    _Getbytes,    PBP,  no
        INT_Handler     USB_INT,  _DoUSBSERVICE,   ASM,  yes
    endm
    INT_CREATE               ; Creates the interrupt processor
ENDASM


;----[Initialise USB and Interrupts]----------------------------------------
    PAUSE 100                    ; Allow VUSB to stabilize
    USBINIT                      ; initialize the USB driver
    USBSERVICE                   ; service it once
    UIE = $7F                    ; enable USB interrupts
    UEIE = $9F                   ; enable USB Error interrupts
@   INT_ENABLE  USB_INT  
@   INT_ENABLE  RX_INT     ; enable RX_INT interrupts




        
USBInit
USBService
Mainloop:
        
        USBService ' Must service USB regularly
        toggle led           'toggle led every loop 
        if flag1 = 1 then
        Gosub readser
        endif
        goto Mainloop






;--------['ISR for RX_int interrupt]------------------------------------- 
        
Getbytes:  
       '###########################################   
       
       While RCIF = 1     ' clear the buffer
        HSERIN 100,error,[Serialdata] ' take it
       Wend
       High led2       'led to confirm program went to RX ISR  
       flag1 = 1  
        


@ INT_RETURN


;----[Interrupt handler -- Service USB]-------------------------------------
DoUSBSERVICE:
      USBSERVICE                   ; Run the SERVICE routines
@ INT_RETURN


error:
      Toggle led1
@ INT_RETURN




usbtx:
USBService
DataRec[0] =13  
USBOut 3, DataRec,13,usbtx
return


readser:
         serin2 PortC.7, 84,[str DataRec\10]     	 
         if DataRec > 0 then 
         gosub usbtx
         flag1=0
         Low Led2      
         ENdif
         Return 
         
 end

The code works, but I think there is a better/right way to do it. Is there a way without the need of using "readser:" label? Any suggestion will be great.
And I also want to insert this code in the main loop..

cnt = 16        ' Specify input buffer size
USBIn 3, buffer, cnt, Mainloop


' Message received
    buffer[0] = "H"
    buffer[1] = "e"
    buffer[2] = "l"
    buffer[3] = "l"
    buffer[4] = "o"
    buffer[5] = " "
    buffer[6] = "W"
    buffer[7] = "o"
    buffer[8] = "r"
    buffer[9] = "l"
    buffer[10] = "d"
    buffer[11] = 13
    buffer[12] = 10
    buffer[13] = 0

But I get "usb device not recognize".

Thanks in advance,
tacbabnon

[tacbanon]

I can now receive data from pc the same time interrupts when data received on portc.7(I was not able to make any changes but any suggestions will be appreciated).
And also I got another question..can I make interrupt for two ports(for incoming data)?

Thanks again,
tacbanon