Help with bluetooth...

[mbox]

Hi everyone, I got an EGBC-04 bluetooth module. When I powered the EGBC-04 my pc detects it(Bluetooth discovery). But I'm having problem communicating with it(sending data only). I place leds to test the communication setup from PC to EGBC04 to PIC16F877A but no luck. Kindly check my setup and codes in the pic....I appreciate any help.

CLEAR		;read and write hardware USART
B1	VAR     BYTE	;initialize USART

    TRISB = %00000000
    PortB = %00000000
	TRISC = %10111111	;set TX (PORTC.6) to out, rest in
	SPBRG = 25	;set baud rate to 2400
	RCSTA = %10010000	;enable serial port and continuous receive
				
LOOP:		
GOSUB CHARIN	;get a character from serial input, if any
	IF B1 = 0 THEN LOOP 	;no character yet
	GOTO LOOP	;do it forever
			;subroutine to get a character 
			;from usart receiver
CHARIN: 
B1 = 0			;preset to no character received
	IF PIR1.5 = 1 THEN	;if receive flag then...
		B1 = RCREG	;get received character to b1

	   IF B1 = 65 then  
	       If PortB.0 = 0 then
	          High PortB.0 
           else
              Low PortB.0
           Endif 	           
	   ENdif
       
   ENdif            
goto loop

Thanks in advance,
mbox

[mackrackit]

I have not used an EGBC-04, but looking at the data sheet I will ask...

Did you set the EGBC-04 for the baud rate you are using? I think it defaults to 9600.
Did you set it as SLAVE? I think that is what you want.

And, I would also think an inverter chip (RS232) is needed.

[mbox]

Hi Dave, I did adjust it to 9600 and do I really need the inverter chip? As I understand I only need it if I directly connect the BT module to the PC. But instead I have a USB bluetooth attached to PC to link with th EGBC-04. Please help..

thanks,
mbox

[mackrackit]

Hi Dave, I did adjust it to 9600 and do I really need the inverter chip? As I understand I only need it if I directly connect the BT module to the PC. But instead I have a USB bluetooth attached to PC to link with th EGBC-04. Please help..

thanks,
mbox

I do not know for sure but to have a PIC communicate with a PC and using hardware serial the inverter chip is needed.

I would think that any data passing through the BT module is inverted. As a quick test you could try SERIN2/SEROUT2 and use inverted mode.

And you have your serial on the PIC set as 2400 baud. The BT is 9600???

[mbox]

Hi Dave, thanks for the replies and I really do appreciate it. Ahm...I'm a little confuse, I hope you dont mind if I'm very slow to pick it all up. But may I explaine my hardware setup to understand what I'm missing.

PC side: [Port - COM7] [Baud rate - 9600] [Byte size - 8] [Stop bit - 1]
Sends character data 'A' over COM7 as given(device discovery).

EBC-04 side: [Operates on 3.3v] [Baud rate - 9600] [Byte size - 8] [Stop bit - 1]

PIC side: [Baud rate - 2400] PortC.7-->Rx

Okay, I understand that I need to change 2400 to 9600 from PIC baud rate to communicate with EGBC. There are two option as I see, either I change the baud rate of the EGBC using AT commands by connecting to the pc with LVTTL TO RS-232 CONVERTER or change PIC's baudrate. But I dont have TTL to RS232 converter right now. So changing the Pic's baud rate is my option. I'm using 4MHZ crystal..how do I change it to 9600?

Thanks,
mbox

[mackrackit]

The easy way to figure the USART settings is to use Mister E's PicMultiCalc
http://www.picbasic.co.uk/forum/showthread.php?t=4994

It gives

 
RCSTA = $90 ' Enable serial port & continuous receive
TXSTA = $24 ' Enable transmit, BRGH = 1
SPBRG = 25  ' 9600 Baud @ 4MHz, 0.16%

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