----- Original Message -----
From: Dr. Imre Bartfai <root@PROF.PMMF.HU>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Monday, October 25, 1999 12:01 PM
Subject: Re: rs232 + 16f84 + 4mc

Thanks!  Changing the org statement did the job! No need to invert since the
code was written for use with an max232.
To late now for trying the transmit code but i assume that will work too
(after changing the org.... )

Aart.

Aart.

> Hi,
>
> when using 16F84, the user RAM begins at 0Ch, rather than at 8. Correct
> your ORG statement! And I guess, the carry must be inverted before sending
> due to the MAX232.
>
> Regards,
> Imre
>
>
> On Fri, 22 Oct 1999, Aart Arenoe wrote:
>
> > Hello,
> >
> > i want to establesh a connection between the 16F84 and the RS232 port at
my computer. The code i use is from the application notes from techtools
Chapter 3, but they are talking about the 16c54 in the example is there a
difference for this usage?
> > Also i'm using a the max232 as shown in the example, but all there is is
rubish at my screen (good old term95). Is there somebody who did manage to
get the pic talking to the RS232? I'm using the CVASM16 assambler. It's not
the computer cause the Universal Infrared Remotecontrol works great on the
same port.
> > Here the code..thanks for your reaction in advance!
> > (i'm using a 4mc christal)
> > Aart.
> >
> >
> > PROGRAM: XMIT232.SRC
> > ; Taken from Parallax PIC Applicaton Note: Sending RS-232 Serial Data
> > ; Written     July 15, 1993
> > ; Revised February 24, 1996
> >
> > ; This program transmits a string of serial data. The baud rate is
determined
> > ; by the value of the constant bit_K and the clock speed of the PIC. See
the
> > ; table in the application note (above) for values of bit_K. For
example, with
> > ; the clock running at 4 MHz and a desired transmitting rate of 4800
baud,
> > ; make bit_K 50.
> >
> > ; >>> Remember to change device info if programming a different PIC! <<<
> > ; Do not use RC devices. Their clock speed is not sufficiently accurate
> > ; or stable enough for serial communication.
> >
> > device pic16f84,xt_osc,wdt_off,protect_off   ; changed the procesor type
from 16c54
> >                                                                ; into
16f84
> >
> > bit_K  = 24                                               ;24 for
9600-baud operation @ 4 MHz
> > serial_out = ra.2                                        ;Output naar
pin 1 van IC
> > org     8                                                    ;Start of
available RAM
> > delay_cntr ds 1                                         ;Counter for
serial delay routines
> > bit_cntr ds 1                                              ;Number of
transmitted bits
> > msg_cntr ds 1                                           ;Offset in
string
> > xmt_byte ds 1                                           ;The transmitted
byte
> > org     0                                                     ;Start of
code space (ROM)
> > jmp begin                                                  ;Start
Programma.
> >
> > begin  mov !ra, #00000000b                        ;Set port to output.
> > mov msg_cntr, #0                                      ;Message string
has nine characters;
> >                                                                 ;0
through 8.
> > :again  mov bit_cntr,#8                               ;Eight bits in a
byte.
> >            mov w,msg_cntr                             ;Point to position
in the string.
> >            call string                                      ;Get the
next character from string.
> >            mov xmt_byte,w                             ;Put character
into the transmit byte.
> >
> >            clrb serial_out                                 ;Change to
setb serial_out for direct
> >
;connection.
> >
> >            call bit_delay ;Start bit.
> >
> > :xmit    rr xmt_byte                                    ;Rotate right
moves data bits into
> >                                                                 ;carry,
starting with bit 0.
> >
> >            movb serial_out,c                           ;Change to movb
serial_out,/c for
> >                                                                ;direct
connection.
> >
> >            call bit_delay                                 ;Data bit.
> >            djnz bit_cntr,:xmit                          ;Not eight bits
yet? Send next data bit
> >
> >            setb serial_out                               ;Change to clrb
serial_out for direct
> >
;connection
> >
> >           call bit_delay                                   ;Stop bit.
> >           inc msg_cntr                                   ;Add one to the
string pointer.
> >
> >           cjbe msg_cntr,#8,:again
> >                                                                 ;More
characters to send? Go to the top
> >
> > :endless jmp :endless                                ;Endless loop.
Reset controller to run
> >
;program.
> >
> > ; To change the baud rate, substitute a new value for bit_K at the
beginning of
> > ; this program.
> >
> >          bit_delay mov delay_cntr,#bit_K
> > :loop  nop
> >          djnz delay_cntr, :loop
> >          ret
> >
> >          string  jmp pc+w                              ;String
consisting of "Parallax"
> >                                                                ;followed
by a linefeed.
> >
> >          retw 'P','a','r','a','l','l','a','x',10
> >
> >
>