Serial port control problem

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xp95

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Hi everybody,
I am working in project which aim to control 80 device through serial port.
First ,I made a simulation by Proteus and virtual port
Second, I used Micro C for Pic programming
Third, C# 2008 for computer interface

The simulation Succeeded but when i try to apply it on 8 devices in reality its failed ( LEDs open randomize)

Can any on tell me the reason?

Here all project files

4shared.com - online file sharing and storage - download Final.rar
 
How are the eight devices connected? Do you have eight RS232 devices sharing the same port? Are each of the eight devices identical but addressable? More info about your project would help here.
 
I put all project files in this link
4shared.com - online file sharing and storage - download Final.rar
which include some pictures of the circuit and simulation files.

How are the eight devices connected?
I put Rs232 to Rs422 conveter to be able to control over than eight devices then connect it in to PIC16F877A in to register 74HC595 which appear in this picture

**broken link removed**
 
Last edited:
hi,
Pin 10 RESET on the CMOS 596 is floating when the RESET switch is open, should have a 10k pull up to +5V.
 
Pin 7 (Q7) and pin 9 (Q7') should not be connected together. They are both outputs and in this case are opposite polarity so they will always be fighting and trying to burn each other out.

An RS232 to RS422 converter will not work between the serial port of the PIC16F877A and an RS232 connector. The serial port on the PIC16F877A is not RS422, it is "TTL compatible" single ended logic levels. How did you connect the 4 wires of the RS422 converter to the 2 wires of the PIC16F877A serial port????
 
mneary said:
Pin 7 (Q7) and pin 9 (Q7') should not be connected together. They are both outputs and in this case are opposite polarity so they will always be fighting and trying to burn each other out.
Click to expand...
sorry this is only mistake in draw

**broken link removed**


May be the wrong in here i will try without conveter thank you
 
You must have a converter between the PIC and RS232, it will probably be called "TTL compatible to RS232". Examples are MAX232, MAX202, MC1488, MC1489. etc.

I just wanted to advise you that it will not be "RS422 to RS232".
 
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