6
Memory Interface and Management
6.1
Memory Management Unit
The MMU provides dynamically allocated ring buffers that hold the data that is in transit between the host, the air or
the Kalimba DSP. The dynamic allocation of memory ensures efficient use of the available RAM and is performed
by a hardware MMU to minimise the overheads on the processor during data/voice transfers. The use of DMA ports
also helps with efficient transfer of data to other peripherals.
6.2
System RAM
56KB of integrated RAM supports the RISC MCU and is shared between the ring buffers for holding voice/data for
each active connection and the general-purpose memory required by the Bluetooth stack.
6.3
Kalimba DSP RAM
Additional integrated RAM provides support for the Kalimba DSP:
■
16K x 24-bit for data memory 1 (DM1)
■
16K x 24-bit for data memory 2 (DM2)
■
6K x 32-bit for program memory (PM)
6.4
Internal ROM
Internal ROM is provided for system firmware implementation.
6.5
Serial Flash Interface
CSR8640 BGA supports external serial flash ICs. This enables additional data storage areas for device-specific
data. CSR8640 BGA supports serial single I/O devices with a 1-bit I/O flash-memory interface.
Figure 6.1 shows a typical connection between the CSR8640 BGA and a serial flash IC.
G
-TW
-0
008502
.1.2
Memory
Management
Unit
Serial Quad I/O Flash
MCU Program
MCU Data
Kalimba DSP Data
Kalimba DSP Program
MCU
Kalimba DSP
QSPI_FLASH_CLK
QSPI_FLASH_CS#
QSPI_IO[0]
QSPI_IO[1]
Serial Flash
Int
erf
ace
CLK
CS#
DI/IO0
DO/IO1
WP#/IO2
RESET#/HOLD#/IO3
1.8V
VDD
Figure 6.1: Serial Flash Interface
CSR8640 BGA supports Winbond, Microchip/SST, Macronix and compatible serial flash devices for PS Key and
voice prompt storage up to 64Mb.
Advance Information
This material is subject to CSR's non-disclosure agreement
© Cambridge Silicon Radio Limited 2011
Page 29 of 110
CS-209182-DSP1
CSR8640 BGA
Data Sheet
