ZBA’s BT44-191 evaluation kit (Fig. 1) includes a Bluetooth dongle to access the BT44-191 eval board. ZBA also has a range of Bluetooth modules. A BT44-191 surface mount leadless chip carrier (LCC) module is included with the kit. It incorporates an antenna on the module so all you need to add is power and a serial link. ZBA also has the BT44-191C module that has a 12-pin, 2-mm, dual-row connector (SAMTEC CLT106-02-L-D). This approach puts it on par with ZigBee, another wireless standard, where modules are a common way to incorporating wireless support into an embedded design without having to resort to FCC approval.
The kit also comes with a CD that has IVT’s BlueSoleil development tools in addition to documentation. The latter includes a handy Antenna Design Guidelines manual.
Like most Bluetooth modules, the 2.40 GHz BT44-191 uses an AT command set. It can handle the enhanced data rate (EDR) specification for 2-Mbit/s and 3-Mbit/s modulation modes. The Piconet support handles up to seven slaves and the module supports Scatternet. The host interface can be serial or USB 2.0. There is even a PCM audio interface in addition to GPIO and SPI. This collection of interfaces means most applications can be handled without any additional support. The main chip has 1 Mbyte of flash memory. Low power modes include park, sniff, hold, and deep sleep.
The BT44-191 evaluation board provides access to all the interfaces on the module. This includes SPI, serial/RS-232, SPI, and audio. It has a rather large power switch and there are plenty of jumpers for configuration. The 5 x 3 button array is handy but the buttons are hard to press. Each button has holes for soldering on headers.
The USB dongle works with IVT’s BlueSoleil tools. BlueSoleil is also a commercial product for managing BlueTooth devices. It is easily installed and works with most Bluetooth devices including the development board.
Initially using the development board is simple with a PC and a serial port or USB connection. You need a standard terminal program, then you can access the device using the AT command set. This was an easy way to test the system and get comfortable with the AT commands and how the module interacts with the PC via the Bluetooth dongle.
Things get more interesting when I connected the evaluation board to a Microchip evaluation kit so we could play with the system via a microcontroller. Overall, it was a trivial exercise since it was just a matter of getting the baud rate settings correct and then delivering the appropriate data streams.
The module approach is much easier than interface to a USB dongle when dealing with microcontroller hosts. The built-in audio support may be useful in many applications. If you are looking to incorporate Bluetooth into an application quickly then check out ZBA’s dev kit. It won’t take long.