![](templates/subSilver/images/CCSLogo.jpg) |
![CCS C Software and Maintenance Offers](templates/subSilver/images/forumAd6.jpg) |
View previous topic :: View next topic |
Author |
Message |
SunShine Guest
|
Error Serial Communication!! |
Posted: Tue Dec 16, 2008 2:40 am |
|
|
MPLAB 8.10 + CCS3.203 + PIC16F877
Hi, I have a problem about RS232 serial communication
I have sucessed to write internal eeprom. but after write I can't use RS232 communication.
Code: | char Control_EEPROM(){
write_eeprom(0x00, serial_Data[3]);
delay_ms(10);
write_eeprom(0x01, serial_Data[2]);
delay_ms(10);
serial_Data[0] = RPY_ACK;
return(1);
} |
|
|
![](templates/subSilver/images/spacer.gif) |
Ttelmah Guest
|
|
Posted: Tue Dec 16, 2008 3:29 am |
|
|
You don't say what is wrong with the serial, but my 'guess' would be that it is going into an overrun error, and no longer receiving.
First comment, you don't need the delays. The write eeprom function already waits for the write to complete. This takes something between 2, and 4mSec, depending on the PIC involved.
Now, you write two bytes to the EEPROM, which with the delays present, will then take possible 28mSec. Assuming your serial is 9600bps, this could be 10 characters arriving. Now the internal buffer in the UART, can handle just a couple of characters. So the UART, goes into an 'overrun' state, _and stops working for receive_.
You need to do two things:
First, add the kyword 'ERRORS' to your RS232 declaration. This adds code to automatically clear this condition.
Second (and more importantly really), you need to _stop_ the serial transmission, while you are writing to the EEPROM. Depending on your serial layout, and the code involved, choices are:
1) Add a simple delay at the transmitting end, after you have send the characters that trigger the EEPROM write.
2) Add flow control to your serial communication.
Best Wishes |
|
![](templates/subSilver/images/spacer.gif) |
|
|
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|