Unformatted text preview: able replacement technology for personal networks. The standard supports a gross data rate of 1 Mbit/s, and uses a frequency hopping scheme and forward error correction to give robust communication in a noisy and uncoordinated environment. 356 Embedded ARM Applications Figure 13.6 Typical GSM handset architecture. The Ericsson-VLSI Bluetooth Baseband Controller chip is a jointly developed standard part which is intended for use in portable Bluetooth-based communication devices. Bluetooth 'piconet' Bluetooth units dynamically form ad hoc 'piconets', which are groups of two to eight units that operate the same frequency-hopping scheme. All of the units are equal peers with identical implementations, though one of the units will operate as master when the piconet is established. The master defines the clock and hopping sequence that synchronize the piconet. Multiple piconets can be linked to form a 'scatternet'. The organization of the Bluetooth Baseband Controller is illustrated in Figure 13.7 on page 357. The chip is based around a synthesized ARM7TDMI core and includes 64 Kbytes of fast (zero wait state) on-chip SRAM and a 4K byte instruction cache. Critical routines can be loaded into the RAM to get the best performance. The cache improves the performance and power-efficiency of code resident in the off-chip memory. There is a set of peripheral modules which share a number of pins, including three UARTs, a USB interface and an I2C-bus interface. FIFO buffers decouple the processor from having to respond to every byte which is transferred through these interfaces. The external bus interface supports devices with 8- and 16-bit databuses and has flexible wait state generation. The counter timer block has three 8-bit counters con- Bluetooth controller organization The Ericsson-VLSI Bluetooth Baseband Controller 357 Figure 13.7 Ericsson-VLSI Bluetooth Baseband Controller organization. nected to a 24-bit prescaler, and an interrupt controller gives control of all on- and off-chip interrupt sources. Ericsson Bluetooth Core The Bluetooth Baseband Controller includes a power-optimized hardware block, the Ericsson Bluetooth Core (EBC), which handles all the Link Controller functionality within the Bluetooth specification and includes...
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- Spring '09