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TDA7500A

Figure 17. DSP1 and DSP0 Memory Spaces

Serial Audio Interface (SAI)

The SAI is used to deliver digital audio to the DSPs from an external source. Once processed by the DSPs, it

can be returned through this interface either sent to the DAC for D/A conversion. The features of the SAI are

listed below.

s

3 Synchronized Stereo Data Transmission Lines

s

3 Synchronized Stereo Data Reception Lines

s

Master and Slave operating mode: clock lines can be both master and slave.

s

Receive and Transmit Data Registers have two locations to hold left and right data.

XCHG Interface (DSP to DSP Exchange Interface)

The Exchange Interface peripheral provides bidirectional communication between DSP0 and DSP1. Both 24 bit

word data and four bit Flag data can be exchanged. A FIFO is utilized for received data. It minimizes the number

of times an Exchange Interrupt Service Routine would have to be called if multi-word blocks of data were to be

received. The Transmit FIFO is in effect the Receive FIFO of the other DSP and is written directly by the trans-

mitting DSP. The features of the XCHG are listed below.

s

10 Word XCHG Receive FIFO on both DSPs

s

Four Flags for each XCHG for DSP to DSP signaling

s

Condition flags can optionally trigger interrupts on both DSPs

DRAM/SRAM Interface (EMI)

The External DRAM/SRAM Interface is viewed as a memory mapped peripheral. Data transfers are performed

by moving data into/from data registers and the control is exercised by polling status flags in the control/status

register or by servicing interrupts. An external memory write is executed by writing data into the EMI Data Write

Register. An external memory read operation is executed by either writing to the offset register or reading the

EMI Data Read Register, depending on the configuration.

DSP1

$FFFF

$0000

X-Space

P-Space

$FFFF

Not Accessible Not Accessible

Y-Space

Not Accessible

$FFFF

Boot-Space

Not Accessible

$07FF

$0800

$00FF

$FFC0

$0100

$FFBF

DSP0

$FFFF

$0000

X-Space

P-Space

$FFFF

Not Accessible Not Accessible

Y-Space

Not Accessible

$FFFF

Boot-Space

Not Accessible

$0200

$FFC0

$15FF

$1600

$FFBF

$01FF

X-Peripherals

Boot-ROM

P-RAM

$0400

$03FF

X-Peripherals

X-RAM

Y-RAM

Boot-ROM

P-RAM

$0400

$03FF

X-RAM

Y-RAM