Navtex Receiver

[mister_e]

Here's a tips on how to mix ASM and PBP.

        '    Using PIC16F88
        @ DEVICE INTRC_OSC, LVP_OFF, WDT_OFF, MCLR_OFF
        
        DEFINE OSC 4
        OSCCON=%01101000
        ANSEL=%00000000
        CMCON=%00000111
        
        trisa = %11111111
        trisb = %00000001
    
        DEFINE HSER_RCSTA 90h ' Enable serial port & continuous receive
        DEFINE HSER_TXSTA 24h ' Enable transmit, BRGH = 1
        DEFINE HSER_SPBRG 25  ' 9600 Baud @ 4MHz, 0.16%
        DEFINE HSER_CLROERR 1 ' Clear overflow automatically
            
        CounterA    var byte BANK0
        CLEAR
        
Start:
        asm
                CHK?RP PORTB
                BTFSC   PORTB,0
                GOTO $-1
                INCF _CounterA,F
        ENDASM                
        HSEROUT ["CounterA=",DEC CounterA,13,10]
        PAUSE 200
        GOTO START

You define your variable in PBP, then you access them in ASM. Possible to use the other way... BUT not 100% sure if this is safe though... sure it isn't 'cause you can't know for sure where PBP will place it's own variables.

[santamaria]

Thanks for your reply mister_e. Tomorrow i will try in PBP and i will tell you my results.

[santamaria]

i am using darrel's interrupts and 20MHz crystal. With mister_e calculator i found that i want prescaler 1:32 and preload 99 into tmr0.I don't know how to preload the value into timer.below i have the interrupt routine of my program. Is this correct for preload the value?


'---[TMR0 - interrupt handler]--------------------------------------------------
Tick0: ;every 1ms occurs

;make space for new sample
cp_old=cp_new ;save old value
cp_new.highbyte=CCPR1H ;take new capture
cp_new.lowbyte=CCPR1L
gosub samplebit ;take the sample bit

TMR0=99

@ INT_RETURN

thanks

[mister_e]

if you're still using the 16F876 and want to have an interrupt each ~1mSec.. then yes.

Easy huh?

[santamaria]

Thanks mister_e.it was very easy to be true. I would like to ask you what is in your timer calc the re-load variable because i can't understand it.

thanks again for you reply.

regards

[mister_e]

If you know how much clock instruction cycle it takes to reload your timer, you set Reload (instr. cycle) (some call it fudge factor) with this value to fine tune your Preload results.

If you don't know AND/OR don't need 100% accuracy, just forgive it

I understand how and why i'd place it there... but the language barrier stop me today... Darrel, Bruce, someone?