Posts Tagged “bluegiga”

In order to make the most of the fact that I have had to test out the PCM interface from Cinterion modules and from Bluegiga Bluetooth modules, I will post about it as it will be of great help to those who want to develop a hands-free GSM device (via Bluetooth). In order to not complicate matters, I will post the information in a simplified, practical way. Well, here we go…

1.- Let’s take a DSB75 evaluation board where we insert the Cinterion GSM module that we want to use (a TC63i, a TC65i, a PH8 etc.) In my case I have a TC65i.

2.- Locate the pins on the DSB75 evaluation board that correspond to the PCM audio pins. They specifically correspond to the board’s x703 connector. In this connector we will see 7 pins: TXDAI, RXDAI, FS, BITClk, FSIN, BCLKIN and GND.


3.- Out of these 7 pins, we only need 5 that are using PCM. The choice you make will depend on whether you use the Cinterion module in PCM MASTER mode or PCM SLAVE mode.  If you use the Cinterion module in PCM MASTER mode, use the TXDAI, RXDAI, FS, BITCLK and GND pins. If we use the Cinterion module in PCM SLAVE mode, use TXDAI, RXDAI, FSIN, BCLKIN and GND pins. The following photo shows how I used it in SLAVE mode with the cables connected to these 5 pins.


4.- We took a Bluegiga development kit (the simplest to use is the WT32 Bluetooth module). The reason for choosing this kit is because it has the PCM pins available in the development kit’s PCB. In Bluegiga’s PCB you can easily see where the PCM pins are due to the good screen.


5.- Connect the GSM Cinterion’s PCM pins with the Bluegiga WT32 Bluetooth module’s PCM pins. Basically you have to connect the pins as follows:

TC65i  (Slave)    WT32 (Master)

RXDAI             OUT
TXDAI             IN
FSIN                SYNC
BCLK               CLK
GND                GND

What if you want the opposite? If we wanted to use the GSM module in MASTER mode it would be like this:

TC65i  (Master)   WT32  (Slave)

RXDAI              OUT
TXDAI              IN
FS                       SYNC
BITCLK            CLK
GND                  GND

So once you have done this, all of the hardware is connected. Now you need a Bluetooth hands-free earpiece. I have one from Plantronics with MAC Bluetooth: 00:03:89:a5:a6:72 (I mentioned it because I will use it later).

6.-The next step is to configure the WT32 Bluetooth module to route audio to/from the PCM interface. We do this by sending the following command to the WT32 module via a HyperTerminal at 115200,8,N,1:


7.- We’ve set up the PCM configuration to the Bluetooth module. Due to the complexity of the different PCM configurations, we use an Excel provided by Bluegiga. With this excel we can indicate the configuration that we want and this way we easily obtain the PSKEY_PCM_CONFIG32 value that we need to configure the PCM. In this case PSKEY_PCM_CONFIG32 has a value of 0×08400000.


As in the previous point we can configure the PSKEY by a command from the HyperTermainal:

SET CONTROL PCM 08400000 006C

8.- Now we are going to configure the Cinterion GSM module to use the audio’s digital interface. These commands can have different functions depending on the model used. I am going to do it with a TC65i. Therefore, from a HyperTerminal we send:


So let’s configure the module to use the PCM digital audio in SLAVE mode at 512MHz and Long Frame.

At this point we have already configured both the Bluetooth module and the GSM module.

So now let’s try the audio!!!!

9.- From the Bluetooth hands-free earpiece (that I imagine is already paired with the Bluegiga Bluetooth module), we can connect to the Bluegiga Bluetooth module (by pressing the only button that it has).

10.- Next we physically connect the TC65i module’s ASC0 RS232 serial port to the WT32 Bluetooth module’s serial port with a serial cable crossover.

11.- We make a GSM audio call from a mobile telephone to the TC65 GSM module. On receiving the call, the module lets out a “RING” from the serial port that will be received by the Bluetooth module in order to inform the Bluetooth earpiece that there is an incoming call (we hear the typical beep beep of an incoming call). We answer the call by pressing the button on the Bluetooth earpiece.

12.- Once you have done this, we answer the voice call in the GSM module with the typical ATA command. If everything has gone well up to now, we will be talking with our hands-free Bluetooth earpiece, connected via Bluetooth to the Bluegiga WT32 module and this in turn is connected to the Cinterion GSM module through the PCM interface.

Well, that’s all for today. This post is perhaps a bit complicated to understand if you don’t have the devices in front of you. But you’ll see that if you ever need to do something similar, this post will be a gem and it will save you lots of working hours. I’ll be fine if I ever need to do it again because I have had to assemble this 3 times over the years. I always think that I won’t forget how to do it but something always slips my mind. From now on this won’t happen ;)



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I have wanted to write a post about this for quite a while in case somebody would find it useful. It’s about providing Bluetooth connectivity to our Siemens TC65 or MTX65 modems. To do this, by way of example I will describe how to make a Bluetooth-GPRS gateway. At first glance, this type of gateway may not seem useful but as I say by way of example I will give you some ideas. Maybe it makes sense in other applications. For example let’s imagine a project where we want to have Bluetooth connectivity with a machine controlled by an MTX65 that has an embedded Java program. For example with Bluetooth a person who has a PDA can maintain it without having to connect any cables or open any machine.

I’m going to go through it very quickly, let me know if you have any questions as I’m just going to describe how to make the application without going into too many details.

To do this I am going to use an MTX65 modem with the MTXTunnel application embedded inside and a Bluegiga WT11 Bluetooth module that I will use with its development board (the MTX65, the MTXTunnel firmware and the WT11 are all distributed by Matrix in Spain). The reason for using the WT11’s development board is because it has an RS232 port and it’s very easy to connect it to an MTX65 simply with a serial cable. Remember that the WT11 Bluetooth module is in class 1 and therefore theoretically we will have a range of about 100m. If we want a smaller range we can choose the WT12 which is a class 2 Bluetooth module that theoretically has a range of about 20m.

gateway bluetooth gprs

On the other hand I will use my amazing Fujitsu-Siemens T830 mobile with Windows Mobile :) I installed the mobile version of this onto my mobile from the well known puTTY terminal (a small program similar to a HyperTerminal).

The SPP (Serial Port Profile) must be enabled in the Bluetooth module’s configuration. All you have to do to check this is find out the SET command response which is sent to the WT11 from a PC with a HyperTerminal connected. This command shows the current settings.

If you have already enabled the SPP in the WT11 Bluetooth module and you have already configured the MTXTunnel configuration parameters (the client mode, the IP and the port the server will connect to), we can connect the WT11 Bluetooth module to MTXTunnel (through the RS232 connector in the development kit) and supply power to both. By doing this MTXTunnel will automatically connect to the IP address and the specified ports via GPRS. The WT11 will keep waiting to receive an incoming Bluetooth connection.

Now touch the phone. First, install puTTY. Once this is installed we have to pair the phone up with the WT11 via Bluetooth. With the telephone’s Bluetooth connection manager, you can find out the WT11’s Bluetooth services in which you should see the SPP (Serial Port Profile). After this is done, we will link this serial port to one of the phone’s virtual COMs.

Terminal pocketPutty

Now launch the puTTY application and open the COM that is associated to the SPP profile that we linked up earlier. When you are opening the COM with the puTTY, what you are really doing is connecting to the WT12 via Bluetooth. Once the COM is open (i.e. the Bluetooth connection is established), everything that is sent through the terminal (puTTY) from the phone to the WT12 is via Bluetooth. The WT12 then sends it through the (development board’s) serial port to the MTX65 (remember that both are linked by a serial cable). Then the MTX65 sends it to the IP address and the previously specified port via GPRS i.e. we have a Bluetooth-GPRS gateway.

I hope that this has been interesting for some of you, as you can see incorporating Bluetooth connectivity into Bluegiga modules or Siemens/Cinterion modems is really simple. See you next time. ;)  

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