PIC16F876A can't interpret RX data

[camy990]

I'm unable to make pins C0 and C1 to respond to incoming commands over rs232, (device=PIC16F876A, compiler = PCW). Am I missing something in the following codes? Please help!!! Any info would be appreciated.

#include <16f876A.h>
#fuses HS,NOLVP,NOWDT,PUT
#USE delay(clock=20000000) #use rs232 (baud=4800, PARITY=E, xmit=PIN_C6, rcv=PIN_C7)
#include <input.c>
#include <string.h>
#define CAM_TYPE_TX PIN_B1
#define NEAR PIN_C0
#define FAR PIN_C1
#define CAM_TYPE_RX PIN_A5
#define CAM_TYPE 200
#define SWITCH_MODE PIN_C4
char rx[20],n[20],f[20];

void RZ5_MODE ()
{
strcpy(n,":WFCBBAA");
strcpy(f,":WFCBBA9");
rx[0] = getc();
putc(rx[0]);

if (strncmp(rx,n,8)==0)
{
output_low(FAR);
output_high(NEAR);
}
else if (strncmp(rx,f,8)==0)
{
output_high(NEAR);
output_low(FAR);
}
else
{
output_low(NEAR);
output_low(FAR);
}
}
void CAM_TYPE_TX_send ()
{
output_high(CAM_TYPE_TX);
delay_ms(50);
output_low(CAM_TYPE_TX);
}
void main()
{
int reading;
output_high(PIN_C4);
output_low(PIN_C0);
output_low(PIN_C1);
setup_adc_ports (RA0_ANALOG);
setup_adc (adc_clock_internal);
set_adc_channel (0);
CAM_TYPE_TX_send();
while(TRUE)
{
delay_ms(50);
read_adc (0);
reading = read_adc();
if ( reading < CAM_TYPE)
{
output_high(SWITCH_MODE);
RZ5_MODE();
}
else
{
output_low(SWITCH_MODE);
}}}

[Wayne_]

You are missing quite a lot, using the code tags in your post would make it readable for a start but your main problem is that you are constantly overwriting index 0 of your rx array with the character from the rs232 port.

basically you will never create the required string.

A quick fix is to have a global index variable and increment it everytime you read in a char:-

[Douglas Kennedy]

Learn to break your code down into functional pieces. Look at rx are you filling it or just writing to rx[0]. After you have rx the way you expect add in another functional piece like comparing it to an expected value. When that works move to the next functional piece. Test the pieces independently for example test the ADC before merging it with your RS232 code. Writing code and throwing at the wall to see what sticks rarely is going to work. Taking another's code and modifying it without first understanding it also rarely works.

[camy990]

I got it to work!!! Thank you all for your excellent direction.