how to accept value from other pic?

janet · Joined: 17 Feb 2004 Posts: 23

/*
sensor.c
*/
#include <16F877A.h>
#device adc=8
#use delay(clock=20000000)
#fuses NOWDT,HS, PUT, BROWNOUT, NOLVP

// #use rs232(baud=9600,xmit=PIN_C6,rcv=PIN_C7)
// i exchange pin_c6 & c7 because 2 ports are connected directly

#use rs232(baud=9600,xmit=PIN_C7,rcv=PIN_C6)
#use i2c(Master,Fast,sda=PIN_C4,scl=PIN_C3)

void main() {

while (1) {
printf("Hello World!");
}

}

/*
receiver.c
*/

#include <16F877A.h>
#device adc=8
#use delay(clock=20000000)
#fuses NOWDT,HS, PUT, BROWNOUT, NOLVP
#use rs232(baud=9600,xmit=PIN_C6,rcv=PIN_C7)
#use i2c(Master,Fast,sda=PIN_C4,scl=PIN_C3)

#USE RS232(BAUD=9600, XMIT=PIN_C6, RCV=PIN_C7, STREAM=RS_DEBUG)
#USE RS232(BAUD=9600, XMIT=PIN_B6, RCV=PIN_B7, STREAM=RS_DATA)

void main() {

while (1) {

fprintf(RS_DEBUG, "--%C", fgetc(RS_DATA));
}

}

I got 2 rs232 port on receiver. one is for debugging, one is for receiving data from sensor.
However, it only generates rubbish on the screen, but not "Hello World"

How to display data from other PIC via rs232?

cheers

Guest · Posted: Sun Mar 21, 2004 2:13 pm

Janet,

i've jyst strated doing this, but all i do is, printf on 1 pic and getch on the 2nd part, rx on c6 and tx on c7

Konrad · Joined: 15 Sep 2003 Posts: 34

Do not swap C6 & C7. Theses are the hardware UART pins, and by swapping them the compiler reverts to the software UART which is by no means as good.
Use the hardware UART for any stream that needs an input.
The software UART is best for simple output (DEBUG).

Add the ERRORS directive to your #use rs232

Add a delay between the printf("hello world") function.

janetsmith2000@yahoo.com · Guest

Which #use rs232 statement?
sensor or receiver?

Guest · Posted: Sun Mar 21, 2004 5:55 pm

I'd rather add a stream identifier in each of the #use rs232() function. Use it this way:

for debugging...
fprintf(com1,"<text here>",variables)

for getting data....
fgetc(com2)

Hope this helps...

dyeatman · Joined: 06 Sep 2003 Posts: 1913 Location: Norman, OK

What screen are you displaying on? The PC screen?

If so, how are you connected between the PIC and the PC? Are you using an RS232 converter chip or direct connecting?

For the hardware outputs you must use an RS232 converter like the MAX232 or MAX233 (which inverts the signal) or an inverter of some sort like the SN7404. For the software UART you may need to use the INVERT keyword for USE RS232

janet · Joined: 17 Feb 2004 Posts: 23

ok,

since i got 2 rs232 port, how many max232 i have to use?

SherpaDoug · Joined: 07 Sep 2003 Posts: 1640 Location: Cape Cod Mass USA

janet · Joined: 17 Feb 2004 Posts: 23

actually the sensor pic is very near with the receiver pic. I use rs232 so that i could change the sensor easily.

unfortunately, the RS_DATA doesn't work and receive nothing.