Wipro to roll range of Bluetooth basebands

"We were determined to develop the basic building blocks, although we knew we didn't yet have the RF expertise," said Uday Ramachandran, global R&D solutions technical manager for Wipro Technologies.

As a result, the product covers the baseband only and includes interfaces to a radio transceiver and to a controlling ARM processor and voice codec. The core's characterized interface to an external ARM7TDMI is through the ASB bus. Voice data transfers are supported by an interface to an external codec unit for those circumstances in which the Bluetooth 1-Mbit/second channel is used to carry voice.

Designed for integration within a broad range of personal and mobile equipment, the solution can be validated using Wipro's test environment or Wipro's protocol stack. This includes the baseband firmware, link manager protocol (LMP), host controller interface (HCI), logical link control and adaptation protocol (L2CAP), service discovery protocol (SDP) and RFCOMM.

Ramachandran said his team of engineers had developed a software version in C, the protocol stack in C and a synthesizable Verilog version and hoped to cross-license the baseband for a Bluetooth radio transceiver. Until then, Ramachandran is demonstr ating the various versions of the interface with publicly available third-party RF sections.

According to Ramachandran, the Bluetooth baseband core offers flexibility, efficiency and a low gate count. In the software-only version, Ramachandran estimates that the only hardware is about 5,000 gates of RF interface. With an accelerator for the mandatory encryption of data, it goes up to 10,000 to 15,000 gates, and the hardware version of the design has fewer than 30,000 gates, said Ramachandran.

At the same time, his organization is geared up to provide design services around the core and take it through to ASIC or system-on-chip implementation. "We are willing to customize the design," said Ramachandran.

Currently, the demo platform is an ARM7TDMI development board either running the C version of the interface or with Verilog blown into FPGA. "By mid December, we hope to have certification in place," said Ramachandran.

Wipro is a technology design center for ARM Holdings plc and is a partner with Symbian, proprietor of the EPOC32 operating system.

However, although the baseband controller is designed to work with an ARM7TDMI core, it can be customized to work with other processors. Similarly, the protocol stack has been ported first to eCOS, a royalty-free configurable real-time operating system. The source code for eCOS is available from Red Hat Inc. and support is available from Red Hat Inc. (Durham, N.C.). Ramachandran said the Wipro Bluetooth protocol stack has been written to operate on a virtual kernel interface, which should ease migration to third-party system environments.

Wipro plans to charge initial license fees followed by per-reuse license fees and unit royalties. Ramachandran said up-front license fees would be on the order of "six figures."