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young
Joined: 24 Jun 2004
Posts: 285
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| RS232 mess communication |
 Posted: Wed Sep 22, 2004 9:59 am |
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I am using a software RS232 communication on 16f819, the program is down here:
| Code: |
#if defined(__PCM__)
#include <16F819.h>
#fuses INTRC_IO,NOWDT,NOPROTECT,NOLVP
#use delay(clock=8000000)
#use rs232(baud=9600, parity=N, xmit=PIN_A0, rcv=PIN_A1)
void main()
{
// printf("start1!");
puts("Start2!");
while(1) {
while(getc()=='a')
delay_us(5);
{
// putc('B');
puts("what happened!");
// output_low(PIN_A0);
}
}
}
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what I saw in the hyperterminal is something strange like this
| Quote: |
\0Aat h���\0DD
�what ���ene�HC�what happe�YVj\0AD0D
what happe�YVj\0A
�what happ��YVj\0A w��B��������\0D
�what happened!\0Dhat happened!\0DD |
I trieed B6, B7; B4,B5; also as TXD and RCV, all I got is similiar like the above, what is wrong with my program? |
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asmallri
Joined: 12 Aug 2004
Posts: 1635
Location: Perth, Australia
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| Posted: Wed Sep 22, 2004 3:18 pm |
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| A couple of possibilities come to mind. 1. There is something wrong with the voltage levels coming from your level converter. If using a MAX232 type device, check for presence of +9 and -9 volt levels (approx) at the V+ and V- terminals. Alternative 2, there is a bit timing problem - are you using a crystal? |
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ckielstra
Joined: 18 Mar 2004
Posts: 3680
Location: The Netherlands
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| Posted: Wed Sep 22, 2004 4:40 pm |
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Sometimes the text 'what happened' comes trough OK, to me this means your baudrate and electronics are most likely alright. What I think is very strange are the '\0A' and '\0D' sequences, these are the CR and LF characters added by the puts() function but normally you wouldn't see them on the screen like this. My guess is your Hyperterm is configured for emulating some weird kind of terminal instead of the default ANSI terminal emulation. Check the setting for emulation settings under File/Properties of Hyperterm.
By the way, Hyperterm is a terrible program for serial communication, it has caused me a lot of troubles in many different ways. |
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Humberto
Joined: 08 Sep 2003
Posts: 1215
Location: Buenos Aires, La Reina del Plata
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| Posted: Wed Sep 22, 2004 4:58 pm |
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| Quote: |
#fuses INTRC_IO,NOWDT,NOPROTECT,NOLVP
#use delay(clock=8000000)
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If you are using a Xtal oscillator it should be
| Code: |
#fuses XT,NOWDT,NOPROTECT,NOLVP
#use delay(clock=8000000)
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If you are using the internal oscillator, the frequency
should be defined with setup_oscillator() function
OSC_8MHZ in your case.
Hope this help
Humberto |
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