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foxOnTheRun
Joined: 17 Apr 2010 Posts: 43
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RS232 weird behaviour |
Posted: Thu May 20, 2010 4:54 am |
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I'm using a 16F688 with it's built in uart:
Code: | #use rs232(uart1,baud=9600,stream=sdcard,PARITY=N,BITS=8,STOP=1)
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I've wired it to a openLog module from sp***fun (not sure if i can write full name, so..) which has an uart too; both are working with logic level so 0..5V.
Also, using a max232 I've linked the pc to the serial line, so I can monitor what's going on (using putty).
At power up the program only execute 2 simple instructions:
Code: | fputc(0x0D,sdcard); |
This is an ENTER, I've seen some garbage already appearing on the line, so I force them out by forcing the other board to try to process it.
Code: | fprintf(sdcard,"Hello world\r"); |
This is where things get interesting, monitoring the line, on the terminal (I use putty) I only capture "ello world", the first char is missing..
Again, if I send:
Code: | fprintf(sdcard,"new test.txt\r"); |
Which is a valid command for the serial board, I get as reply "ew test.txt unknown command".. so actualy the system is eating the first char - gosh!
The PIC and the board are directly connected, TX and RX pins are inverserly matched - are there some extra settings or issue to take care of when setting up a serial link?
This is the full main.c as reference (yes, there is a LCD16x2 connected to the PIC).
Code: |
#include main.h"
#include LCD.C>
#include <string.h>
#include <stdlib.h>
#include <limits.h>
#define LED PIN_A0
char str[80]="";
int i=0;
int n=0;
int f=0;
int log=0;
#use delay(clock=8000000)
#int_RDA
void RDA_isr(void)
{
str[i]=getch(sdcard);
i++;
if (i>79) i=0;
}
#use delay(clock=8000000)
void main()
{
setup_adc_ports(NO_ANALOGS|VSS_VDD);
setup_adc(ADC_OFF);
setup_timer_0(RTCC_INTERNAL|RTCC_DIV_1);
setup_timer_1(T1_DISABLED);
setup_comparator(NC_NC_NC_NC);
setup_vref(FALSE);
enable_interrupts(INT_RDA);
enable_interrupts(GLOBAL);
setup_oscillator(OSC_8MHZ);
output_low(LED);
output_high(LED);
lcd_init();
printf(lcd_putc,"\fCard INIT 3s..");
delay_ms(3000);
output_low(LED);
printf(lcd_putc,"\fLogging..");
fputc(INVIO,sdcard);
fprintf(sdcard,"Hello world\r");
while(1);
} |
_________________ Listen, why don't you relax? Take a pill, bake a cake or go and read the encyclopedia. |
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Wayne_
Joined: 10 Oct 2007 Posts: 681
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Posted: Thu May 20, 2010 7:13 am |
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What is INVIO ? |
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foxOnTheRun
Joined: 17 Apr 2010 Posts: 43
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Posted: Fri May 21, 2010 2:55 am |
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Oh, I forgot, it's a define for ENTER = 0x0d. _________________ Listen, why don't you relax? Take a pill, bake a cake or go and read the encyclopedia. |
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languer
Joined: 09 Jan 2004 Posts: 144 Location: USA
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Posted: Mon May 24, 2010 1:16 am |
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What are your "#use rs232" and "setup_uart" (if used) definitions? |
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Wayne_
Joined: 10 Oct 2007 Posts: 681
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Posted: Mon May 24, 2010 3:30 am |
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I assume you have
PIC TX -> Module RX & PC RX
PIC RX <- Module TX (only ?)
What do you get on the PC if you disconnect the module and just have Pic to PC ? |
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foxOnTheRun
Joined: 17 Apr 2010 Posts: 43
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Posted: Fri May 28, 2010 5:14 am |
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languer wrote: | What are your "#use rs232" and "setup_uart" (if used) definitions? |
First post, first 2 lines:
Code: | #use rs232(uart1,baud=9600,stream=sdcard,PARITY=N,BITS=8,STOP=1) |
_________________ Listen, why don't you relax? Take a pill, bake a cake or go and read the encyclopedia. |
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foxOnTheRun
Joined: 17 Apr 2010 Posts: 43
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Posted: Fri May 28, 2010 5:18 am |
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I found something:
if I send: 0x0d (return) to confirm the data/commands the system was behaving wrongfully.
If I send printf("text-or-commands\n\r") the system was back in operation as it should.
So, I can consider the question closed, the "fault" looks like is on the receiver side.
The PIC connected to the PC was behaving perfectly fine. :) _________________ Listen, why don't you relax? Take a pill, bake a cake or go and read the encyclopedia. |
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