serial communication between two pic with RF modules - Electronic Circuits Projects Diagrams Free

amindzo · 14th August 2006, 08:39 AM

Hi,
i send the sensor data to RF transmitter with serial communication(1-wire) then on the reciever board
RF reciever get the data and send it to the micro by serial comunication and show it on lcd.
i should send the sensor data every 5 minutes and during this time micro goes to sleep mode.
after two or three transfering , i can't see anything on lcd but after restarting the micro
it works without any problem.
why do you think after 2 or 3 transfering this problem is occuring?
how can i solve the problem?
is it about software?
i use microcode sudio picbasic pro2.41 .
i use serin and serout instructions for serial communication.

M_S_U · 15th August 2006, 11:39 AM

hi..
First of all you send preamble which are 5 byte of 0x55 or 0xAA...Then send 5 byte 0x00 and 5 byte 0xFF for obtain synchron.. Perhaps it causes the problem...

amindzo · 15th August 2006, 12:22 PM

hi,
are you sure that i should send that 25 bytes befor sending my data?
my problem is that after recieving data for 3 or 4 times ,something wrong happen to the data and i can't see anything on lcd.do you think that my problem will solve by sending that preamle bytes befor my dada bytes?

mramos1 · 15th August 2006, 12:28 PM

You have a pullup on the reset pin?

amindzo · 15th August 2006, 06:13 PM

yes, i put a 4.7K resistor between reset pin and vcc.(pin number 1 in pic16f873a).this is not my problem. could you help me more?

**Nigel Goodwin** · 15th August 2006, 06:43 PM

You might try reading my PIC RF tutorial?, it's not a good idea to try and send standard serial data over a radio link, you should encode it in some way (Manchester coding, or some other NRZ system). A radio link is AC coupled, RS232 is DC coupled - that's the first problem!.

amindzo · 15th August 2006, 09:46 PM

i use haming code.
is it good for my application?
should i send some preamble bytes?

**Nigel Goodwin** · 16th August 2006, 09:25 AM

Quote:

Originally Posted by amindzo

i use haming code.
is it good for my application?
should i send some preamble bytes?

I wasn't aware that haming code was of any help for RF?, and if you're using the inbuilt serial routines of PICBASIC then you're just sending plain serial?.

M_S_U · 16th August 2006, 04:59 PM

I have done it by PICC...I sent preamble+sencron before sending any data...After sending data i waited 80 Us for 1200 baud after each data sending...But i'm not sure that this application can solve your problem...

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14th August 2006, 08:39 AM	#1
amindzo	serial communication between two pic with RF modules Hi, i send the sensor data to RF transmitter with serial communication(1-wire) then on the reciever board RF reciever get the data and send it to the micro by serial comunication and show it on lcd. i should send the sensor data every 5 minutes and during this time micro goes to sleep mode. after two or three transfering , i can't see anything on lcd but after restarting the micro it works without any problem. why do you think after 2 or 3 transfering this problem is occuring? how can i solve the problem? is it about software? i use microcode sudio picbasic pro2.41 . i use serin and serout instructions for serial communication.

15th August 2006, 11:39 AM	#2
M_S_U	hi.. First of all you send preamble which are 5 byte of 0x55 or 0xAA...Then send 5 byte 0x00 and 5 byte 0xFF for obtain synchron.. Perhaps it causes the problem...

15th August 2006, 12:22 PM	#3
amindzo	hi, are you sure that i should send that 25 bytes befor sending my data? my problem is that after recieving data for 3 or 4 times ,something wrong happen to the data and i can't see anything on lcd.do you think that my problem will solve by sending that preamle bytes befor my dada bytes? Last edited by amindzo; 15th August 2006 at 12:26 PM.

15th August 2006, 12:28 PM	#4
mramos1	You have a pullup on the reset pin?

15th August 2006, 06:13 PM	#5
amindzo	yes, i put a 4.7K resistor between reset pin and vcc.(pin number 1 in pic16f873a).this is not my problem. could you help me more?

15th August 2006, 06:43 PM	#6
Nigel Goodwin	You might try reading my PIC RF tutorial?, it's not a good idea to try and send standard serial data over a radio link, you should encode it in some way (Manchester coding, or some other NRZ system). A radio link is AC coupled, RS232 is DC coupled - that's the first problem!. __________________ PIC programmer software, and PIC Tutorials at: http://www.winpicprog.co.uk

15th August 2006, 09:46 PM	#7
amindzo	i use haming code. is it good for my application? should i send some preamble bytes? Last edited by amindzo; 15th August 2006 at 09:51 PM.

16th August 2006, 04:59 PM	#9
M_S_U	I have done it by PICC...I sent preamble+sencron before sending any data...After sending data i waited 80 Us for 1200 baud after each data sending...But i'm not sure that this application can solve your problem...