Interupts and Command string

[Tissy]

Hi,

I am trying to alter the below piece of code for an interupt driven serial device.

I would like the 'Main' part of the program to run up until a serial command is received. I would also like the device to send comms back to VB, this is the reason i have inserted 'flags'.

The interrupts are only working with a single character. How would i use the interrupt so that it receives a string of commands.

ie using the SERIN command i would use SERIN RxD,baud,[WAIT(254), hrs, min, sec], can someone assist how would i achieve this using interrupts. I would like it so that when the command (254) is received it then stores the received hrs, min and sec variables in EEPROM.

If i can achieve this then it should be a good starting block to the rest of the code.

    '
    '   Simple program to handle USART interrupt using PIC16F877 @20MHZ
    '   ===============================================================
    '
    '   This program will Blink a LED on PORTB.0 to show
    '   that the PIC is running.  
    '
    '   This program also allow the user to activate or deactivate 
    '   a LED connected on PORTB.1 pin by sending command from a PC
    '   terminal software using 9600,n,8,1 setting
    '
    '   User command:
    '   =============
    '                1. If character "1" is received => enable the LED
    '                2. if character "2" is received => disable the LED
    '
    '
    DEFINE LOADER_USED 1        ' using bootloader
    DEFINE OSC 20               ' running at 20 MHZ
    ADCON1 = %00001111
    
    '    PORT setting
    '    ============
         '
         TRISC=%10000000        ' RC.7 => USART RX pin set to input
                                ' all other pin set to output
                                '
         TRISB=0                ' RB<7:0> set to output
    
    '    USART setting
    '    =============
         ' Since we will not use HSERIN/HSEROUT, we must
         ' write directly to internal PIC register
         ' 
         TXSTA=$24              ' enable transmit and SPBRGH=1
         RCSTA=$90              ' Enable USART and continuous receive
         SPBRG=129              ' BAUD RATE = 9600 BAUDS
   
    '    Interrupt definition
    '    ====================
         '
         PIE1.5   =1            ' enable USART receive interrupt
         INTCON.6 =1            ' enable peripheral interrupt
    
    '    Alias definition
    '    ================
         '
         RCIF      var PIR1.5   ' receiver interrupt
         StatusLED var PORTB.0  ' the LED who show a 'running process'
         UserLED   var PORTB.1  ' the LED that user want to control
         
    '    Variable definition
    '    ===================
         '
         Delay      var word     ' 
         DataIn     var word     ' use to store RCREG content
         Discard    var byte     ' use to erase RCREG register
         storedloop var byte
         Flag       var byte
        
    '    Hardware/software initialisation
    '    ================================
         '
         PORTB=0                ' clear PORTB         
         on interrupt goto USARTInterrupt

        
Start:
    '    Main program loop that make the user happy to
    '    see a LED flashing to mean that something is 
    '    running 
    '
    If flag = 1 then hserout [" Device Connected"]
    if flag = 2 then hserout [" LED is Flashing"]
    if flag = 3 then hserout [" LED is ON"]    
    If flag = 4 then hserout [" LED is OFF"]
    flag = 0
    
    toggle statusled
    for delay = 1 to 5000       ' use a loop delay to ensure
      pauseus 5                 ' getting interrupt as fast as
      next                      ' possible
    goto start
    

disable interrupt
USARTInterrupt:
    '    Here's the interrupt routine who will make the user
    '    much happy by giving him the feeling to have the 
    '    control on the machine when the status of the user
    '    LED will change
    '
    RCSTA=0                     ' Disable serial port AND
                                ' clear possible error (FERR,OERR)
                                
    datain=RCREG                ' Get data
                                
    while RCif                  ' wait untill the RCREG is empty
          discard=RCREG         ' by reading it and store result in a
    wend                        ' don't care variable
                                
    select case datain          ' What to do with that data???
                                
           case "#"             ' User selection = 1
                userled=1       '      => Enable the LED
                FLAG = 3         '      => disable the LED
           case "2"             ' User selection =2
                userled=0       '      => disable the LED
                flag = 4
           case "3"             ' User selection =321
                For storedloop = 1 to 5
                    High userled
                    Pause 50
                    Low userled
                    Pause 50
                Next storedloop
                flag = 2
            case "9"             ' User selection =2
                FLAG = 1         '      => disable the LED
                                
           end select
               
    RCSTA=$90                   ' Re-enable the serial PORT AND
    resume                      ' get out of here
enable interrupt

Many thanks for any help offered.

Steve

[mister_e]

I remind that code...You remove my name on the top header

Well why not simply use HSERIN in the USARTInterrupt section?

[Tissy]

Your quite correct Steve, it was your code which i found at http://www.picbasic.co.uk/forum/show...6F877+%4020MHZ

I didn't remove any of your signatures from the top header as they weren't on the code i found as above. All credits recognised though ;-).

Would you be kind enough to give an example of what you mean using the HSERIN command.

As in the interrupt code you are disabling the serial port first. Are you saying remove these lines, and then treat it with just the HSERIN command.

I am new to serial comms and often learn better from a quick example (if you could oblidge).

Many thanks,

Steve

[mister_e]

Yup that's what i think... just an idea.

So you already figured something like

Disable 
USARTInterrupt:
    HSERIN [Data1, Data2,....]
    '
    '    Data processing or not here
    '
    Resume
Enable

Just read the HSERIN section. You may also use STR modifier too. Dpending what kind of data format you'll use.

[Tissy]

Excellent help, thanks.

I have now managed to get variables sent from VB to PIC.

The code now looks like this:

Start:
    '    Main program loop that make the user happy to
    '    see a LED flashing to mean that something is 
    '    running 
    '
    
    Hserout [hours, minutes, seconds]
    
    toggle userled
    for delay = 1 to 5000       ' use a loop delay to ensure
      pauseus 5                 ' getting interrupt as fast as
      next                      ' possible
    goto start
    

disable interrupt
USARTInterrupt:
    '    Here's the interrupt routine who will make the user
    
    HSERIN [hours, minutes, seconds]

    Write 5, hours
    Write 6, minutes
    Write 7, seconds
  
    resume                      ' get out of here
enable interrupt

However, i can only send over single numerals, ie 0-9. But in the timing functions for Hrs, Mins and Sec it could be upto 59. How do i get the PIC to reconise the double figures. If i try to send them the PIC just hangs.

The write command is to just store the variables in EEPROM for later use.

Thanks for your help,

Steve

[mister_e]

Suppose the actual time is 1:33:56
Send it as 013356

actual time is 1:02:01
send it as 010201

THEN you use the DEC2 modifier
HSERIN [DEC2 hour, DEC2 Minute, DEC2 Second]