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Unformatted text preview: the interface logic to a Bluetooth radio implementation. The EBC performs all the packet-handling functions for point-to-point, multislot and point-to-multipoint communications. The baseband protocol uses a combination of circuit and packet switching. Slots can be reserved for synchronous channels, for example to support voice transmission. 358 Embedded ARM Applications Power management The chip has four power management modes: 1. On-line: all blocks are clocked at their normal speed. The ARM7TDMI core clock is between 13 and 40 MHz, depending on the application. At the maximum data transfer rate the current consumption is around 30 mA. 2. Command: The ARM7TDMI clock is slowed by the insertion of wait states. 3. Sleep: The ARM7TDMI clock is stopped, as are the clocks to a programmable subset of the other blocks. The current drawn in this mode is around 0.3 mA. 4. Stopped: The clock oscillator is turned off. Bluetooth system A typical Bluetooth system is illustrated in Figure 13.8. The baseband controller chip requires an external radio module and program ROM to complete the system. The high level of integration leads to a very compact and economic implementation of a sophisticated and highly functional radio communication system. V Figure 13.8 Typical Bluetooth application. Bluetooth silicon A photograph of a Bluetooth die is shown in Figure 13.9 on page 359. The die area is dominated by the 64 Kbyte SRAM, with the synthesized EBC (in the bottom right-hand quadrant) being the second largest block. The synthesized ARM7TDMI core in the top-right corner of the chip has far less visible structure than the ARM7TDMI hard macrocell shown Figure 9.4 on page 255. This is because the hard macrocell was laid out by hand and manual designers use very regular datapath structures to give dense layout and to minimize the number of different cells that must be created. Synthesized cells use less dense and less regular structures. The advantage of the synthesized core is that it can be ported to a new CMOS process much more rapidly. The characteristics of the Bluetooth core are...
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This document was uploaded on 10/30/2011 for the course CSE 378 380 at SUNY Buffalo.
- Spring '09