Bluetooth adapter connection problem

Lynxmotion Electronics & Software
1

Hi,

I recently purchased a bluetooth to serial adapter from LM Technologies.

We were wondering how to connect it the SSC-32.

We were wondering if the DSR/DTR are required to be connected to anything (The adapter has those pins as unconnected). We also tried to reverse the CTS/RTS signals but that didn’t work as well. We fear that it could be because of some incompatible signals or something due to the interface.

We can send data between PC’s using this serial adapter (and hyperterminal) but when we try to send data to the SSC-32, the LED does not flash to indicate it has received anything.

Any help would be greatly appreciated.

2

Try just connecting the TX and RX lines only. This is usually all that’s required. Also make sure the SSC-32 is jumpered for the correct baudrate to match the Bluetooth adapter.

8-Dale

3

Better connect the ground also.

4

Before I try anything, I noticed in the manual that the bluetooth adapter’s default hardware configuration is CTS/RTS… What does that mean exactly?

I have a feeling that the adapter is waiting for the CTS pin to be set high before it will actually send it…

Should I pull the CTS pin constantly high?

5

If it is like the blueSMiRF that you can buy at sparkfun
sparkfun.com/commerce/product_info.php?products_id=582
Their documentation states that if you are not doing hardware flow control you should connect the CTS to the RTS line.

6

That is hardware flow control. The SSC-32 does not require this.

It sounds like this is what is happening. You should try disabling the CTS/RTS (called hardware flow control) on the Bluetooth adapter if that is possible.

8-Dale

7

Hmm, I flipped through the documentation and it looks like there is no way to disable hardware flow control.

Would setting the pin to high 5V work?

8

Connecting the cts and rts lines may make it think it is aligned for hardware control. In my tinkering with serial ports, when a port is opened, rts goes high. Connecting rts to cts will probably put the appropriate voltage on the cts pin. Below is a link that shows some serial port wiring setups.

passmark.com/support/loopback.htm

9

My choice also would be to jumper CTS to RTS on the SSC-32, as the pins are accessible. Just thinking… could it be possible to turn the bluetooth radio on and off by controlling the CTS from the ssc-32 so that some battery power could be saved? Please keep us posted on what works and what doesn’t…

10

RTS (Request To Send) is output usually from the terminal to see if the modem or data device is ready to receive the next byte. If the device is ready it replies with CTS (Clear To Send)…

What the guys are saying is right, on the BlueSmirf it has a link that can be shorted to connect RTS and CTS and fool the unit into thinking its always ready to receive data

The SSC doesn’t need RTS and CTS.

Another thing to check is what level the unit is using. If its at RS232 level then it needs to go in throught the DB9 socket. If its at TTL level then remove the links at the side of the DB9 to disable it and connect your TTL to the three header pins. TX/TX/GND. They are the only three connected to the SSC.

11

On the BlueSmirf it takes 48mA while connecting a link at which point it drops to 24.8mA. A constant stream of data draws 33mA…

Compared to the current by an idle servo its negligible. Putting the servo’s to sleep would save more…

I’ve been working on some UART code and have had the robot turned on in sleep mode with just the SSC and BlueSmirf running and its lasted 4 or 5 hours.

12

A slightly off the topic question :blush: .

Is it possible to hook up the BlueSmirf up to the ABB board? Or would I need to find a different one that can plug into the 9 pin connector?

Thanks

13

If I remember rightly, the ABB has RS232 out of the main chip so theres no TTL level. It can be done but you would need to add a max232 or equivalent to the output of the Smirf before you connected to the input of the ABB.

14

Why does it have to be such a pain in the butt to get these things to work???,
my IOGEAR BT to serial adpter does,nt want to work on my 98 machine i,ve got cts rts jumpered and i can get it to pair but not detect sevices ive tried numerous setting on the on the computer software side ,and i,m thinking thats it a software/driver problem but i cant figure out how to force it to reconize a serial port service any ideas (besides up grading to XP)

15

Behind the scenes, Windows 98 suffers big time. 98SE was better but not much.

Most XP based comms apps implement a stack of some sort, usually TCP which XP understands well but 98 just doesnt.

If you are using a bluetooth driver then there will be a stack somewhere and its quite likely your issues will be, as you surmised, with the drivers.

Its a bind but I usually scour the internet coz someone somewhere has usually had the problem before and has a set of drivers that will work…

16

i,m shure ur right ,probly be best to leave 98 but i doubt that i can find drivers for my hard ware on my old puters ,im tryiny the move to linux but then i will have to give up on roborelm and thats the thing i wont most
(besides wireless programming) well i,m kinda hanging in limbo for awhile :unamused:

17

What about Win 2000. We still use it for development for some customers and it does support older machines.

I have a couple of older gateway and dell laptops and desktops that run fine on it.

Most USB stuff works on 2000

18

i thought about win 2000 last night ,cant remember hearing much about it ,but atlast i figured out my problem it seams it was a unpairing problem on the iogear. i had to switch dip 4 power up power down switch it back and whalla!!! it works again, 8) so on to the next problem