Help with bluetooth...

[dhouston]

But even changing the baud I still think you will need an inverter.

The manual shows two BT module to µC examples and one BT module to PC serial port example. Only the latter uses an inverter (i.e. their RS232 module).

The PIC UART will likely have a Schmidt Trigger input - 3.3V is too low to be seen as logic high - 0.8Vdd is required. With SerIn or SerIn2 and TTL inputs, logic high is 2V.

FIG 14 & FIG 15 of this app note http://www.zbasic.net/appNotes/AN213.pdf shows how to interface to the Schmidt Trigger input.

[mbox]

Hi dhouston, I'm a beginner in electronics and seasonal pbp programmer. I hope I got this one, so in order to communicate properly I must use a Logic Translation Level between EGBC-0 and pic like the one below..
BTW thanks for the link...I will experiment with it and post my updates.

[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.