bah...   fixed the subject line.....


----- Forwarded by Joe Jansen/TECH/HQ/KEMET/US on 03/05/2004 08:59 AM
-----

Joe Jansen/TECH/HQ/KEMET/US wrote on 03/05/2004 08:59:02 AM:

> Hey!  I can finally contribute!
>
> From the datasheet (I am looking at the sheet for the 18f242 that I
> just finished the same type of project for):
>
> <quote>
> NOTE:  TXIF is not cleared immediately upon loading data into the
> transmit buffer TXREG.  The flag bit becomes valid in the second
> instruction cycle following the load instruction.
> </quote>
>
> therefore, your test at a1, which is the first instruction following
> the load, is testing TXIF before it gets updated from loading TXREG.
>
> Hope this helps!
>
> --Joe Jansen
>
> pic microcontroller discussion list <PICLIST@MITVMA.MIT.EDU> wrote
> on 03/05/2004 08:46:19 AM:
>
> > >> I'm experiencing strange behaviour with the 452 and the PLL
enabled:
> >
> > >You do know that the PLL on/off setting takes its (new) effect only
> > after a power down - power up?
> >
> > Yes I do, I found out the hard way the first time I tried to use it
:-)
> >
> > Each time I enable or disable the PLL I remove power and then
reaply...
> >
> > Also I discovered another problem I can't figure out. The following
code:
> >
> >   movlw 'T'
> >   movwf TXREG
> > a1:  btfss PIR1, TXIF
> >   goto a1
> >   movlw 'e'
> >   movwf TXREG
> > b1:  btfss PIR1, TXIF
> >   goto b1
> >   movlw 's'
> >   movwf TXREG
> > c1:  btfss PIR1, TXIF
> >   goto c1
> >   movlw 't'
> >   movwf TXREG
> > d1:  btfss PIR1, TXIF
> >   goto d1
> >   movlw '-'
> >   movwf TXREG
> > e1:  btfss PIR1, TXIF
> >   goto e1
> >
> > That should give "Test-" as a UART output gives only "Ts-"! Baud
> > rate is 19.2Kbps. Even if I put it at a continous loop it keeps
> > displaying "Ts-Ts-Ts-Ts-". The same code with a 877 in place of the
> > 452 works fine.
> >
> > Could it be that my micro is damaged? How could that happen?
> >
> > John Spiliotopoulos/Greece
> >
> > --
> > http://www.piclist.com#nomail Going offline? Don't AutoReply us!
> > email listserv@mitvma.mit.edu with SET PICList DIGEST in the body

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