Help with bluetooth...

[dhouston]

@mbox

The simplest solution would be to use SerIn or SerIn2 on a pin that has a TTL buffer. Read the I/O Ports section of the datasheet for the 16F877a as well as the Electrical Characteristics section. Ports A & B have TTL buffers on the pins and only need 2.0V for logic high.

If you must use the hardware UART, I suggest using the circuit in FIG 15 of the app note. If you use FIG 14, the diode forward voltage drop may be marginal for the logic low input voltage (1.0V) unless you use a germanium diode. Read the explanation in the app note.

EDIT: Also, if you use the diode, use the attached circuit.

[mbox]

Hi to all, I change the codes and Port pin setup, at this time I used the SERIN and SEROUT...

include "modedefs.bas"
B2 var byte 
pause 500

start:   

       serin 0,T9600,B2 ''''''''''''''''''''''''''' PortB.0 as my recieve pin from bluetooth Tx
       Serout PORTC.6, T9600, [#B2,10,13] '''''''''''''''''''''''PortC.6 as Transmit pin	 to pc com1

	   IF B2 = 65 then  
	       If PortB.1 = 0 then
	          High PortB.1 
           else
              Low PortB.1
           Endif 
           else
           	            
	   ENdif
goto start

I noticed that it is generating random numbers pls see the attach...anybody knows what's the reason?

Thanks in advance
mbox

[mackrackit]

Are you sending somthing from the PC and the random numbers are the echo?

[dhouston]

SerOut to the PC serial port needs to be inverted - use N9600.

[mbox]

Hi everyone,

mackrackit: Are you sending somthing from the PC and the random numbers are the echo?

It suppose to lit a LED on PortB.1 when "A" is pressed. Connecting the EGBC TX--> PIC Rx causes the random generation number.

dhouston: SerOut to the PC serial port needs to be inverted - use N9600.

I tried that but it gives character sysmbols..pls see the attachment.

[dhouston]

I tried that but it gives character sysmbols..pls see the attachment.

I'm confused. Your code example comment says "PortC.6 as Transmit pin to pc com1" but your latest schematic appears to indicate another wireless connection to the PC.

A wired RS232 connection needs N9600 for SerOut while a wireless connection may use T9600. A wireless connection may also be noisy, leading to the random data of your first example.

[mbox]

Hi, sorry if it is confusing. I forgot to tell you that I'm using my mobile to send data to the bluetooth module and hopefully have it echoed to the Pc. My code for my phone is tested, it can send letter 'A' from phone to Pc thru bluetooth communication. And hoping it will the same way to pic with a bluetooth module. So this noise is normal? How can I prevent it from generating. I tried to observe while sending from my phone to pic if 65 is recieved, unfortunately it is not.

 IF B2 = 65 then  ' waits for "A"
           If PortB.1 = 0 then
	 High PortB.1 
           else
              Low PortB.1
           Endif 

           else
           	            
Endif