EMBEDDED SOLUTIONS

Case study: Development of Bluetooth serial driver

Customer: One of the first companies to bring certified Bluetooth software to the world
Technology: Embedded; Bluetooth

The Customer

The customer is a leading software provider of Bluetooth™ short-range wireless connectivity solutions, one of the first companies to bring certified Bluetooth software to the world, and a market leader in supplying Bluetooth software and systems to semiconductor, consumer electronic manufactures, and computing device OEMs.

The Challenge

The client had its Bluetooth stack deployed in one of the most widely accepted PDA’s available at that time. The Bluetooth applications were experiencing loss of data while performing large data transfers over the Bluetooth interface. The objective of the project was to develop a new serial device driver to overcome this limitation. Tata Infotech had to design a stream interface device driver for the BTUART port for Intel’s PXA250 XScale processor. The driver was required to act like a standard serial port driver, be accessible using commands such as “open serial port”, support flow control and prevent data loss at high speed. The driver was also required to have an interface that is similar to the HCI UART interface of Bluetooth.

The Solution

Tata Infotech developed the serial driver for the BTUART port of XScale processor. The driver was based on the stream interface device driver model. Bluetooth Serial Driver technology was employed to execute this process.

A two-layered architecture having MDD and PDD layers was developed. DMA was used to transfer data from/to UART FIFO. The DMA buffer chaining mechanism was used for this purpose. The driver supported RTS/CTS flow control. The data transfer was tested by transferring 20MB files between two iPAQs and also by transferring 20MB files between an iPAQ and Desktop PC with Bluetooth support.

The Benefits

• Performance improvement of 15% was achieved for transmission. 
• Improvement of 52% was achieved for reception with the help of the driver. 
• The new driver eliminated the data loss
  

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