BC352239A Datasheet, PDF (31/116 Pages) List of Unclassifed Manufacturers – BlueCore 3-Multimedia External

Description of Functional Blocks
6.5 Baseband and Logic
6.5.1 Memory Management Unit
The Memory Management Unit (MMU) provides a number of dynamically allocated ring buffers that hold the data
which is in transit between the host, the air or Kalimba DSP. The dynamic allocation of memory ensures efficient
use of the available Random Access Memory (RAM) and is performed by a hardware MMU to minimise the
overheads on the processor during data/voice transfers.
6.5.2 Burst Mode Controller
During radio transmission the Burst Mode Controller (BMC) constructs a packet from header information
previously loaded into memory-mapped registers by the software and payload data/voice taken from the
appropriate ring buffer in the RAM. During radio reception, the BMC stores the packet header in memory-mapped
registers and the payload data in the appropriate ring buffer in RAM. This architecture minimises the intervention
required by the processor during transmission and reception.
6.5.3 Physical Layer Hardware Engine DSP
Dedicated logic is used to perform the following:
! Forward error correction
! Header error control
! Cyclic redundancy check
! Encryption
! Data whitening
! Access code correlation
! Audio transcoding
The following voice data translations and operations are performed by the firmware:
! A-law/µ-law/linear voice data (from host)
! A-law/µ-law/Continuously Variable Slope Delta (CVSD) (over the air)
! Voice interpolation for lost packets
! Rate mismatches
The hardware supports all optional and mandatory features of Bluetooth v1.2, including AFH and eSCO.
6.5.4 RAM
32Kbytes of on-chip RAM is provided to support the RISC MCU and is shared between the ring buffers used to
hold voice/data for each active connection and the general purpose memory required by the Bluetooth stack.
6.5.5 Kalimba DSP RAM
Further on-chip RAM is provided to support the Kalimba DSP as follows:
! 8K x 24-bit for data memory 1 (DM1)
! 8K x 24-bit for data memory 2 (DM2)
! 4K x 32-bit for program memory (PM)
BC352239A-ds-001Pc
© Cambridge Silicon Radio Limited 2004
Production Information
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