Motorola DSP56012 User Manual

• User programmable to support a wide variety of serial audio formats

• Three receive interrupt vectors: Receive Left Channel, Receive Right Channel, 

and Receive with Exception

• Three transmit interrupt vectors: Transmit Left Channel, Transmit Right 

Channel, and Transmit with Exception

The SAI is functionally divided into three parts: the baud-rate generator, the receiver 
section, and the transmitter section. The receive and transmit sections are completely 
independent and can operate concurrently or separately. The following paragraphs 
describe the operation of these sections.

The baud-rate generator produces the internal serial clock for the SAI if either or both 
of the receiver and transmitter sections are configured in the Master mode. The 
baud-rate generator is disabled if both receiver and transmitter sections are 
configured as slaves. Figure 6-1 illustrates the internal clock path connections. The 
receiver and transmitter clocks can be internal or external depending on the 
configuration of the Receive Master (RMST) and Transmit Master (TMST) control 
bits.

Figure 6-1  SAI Baud-Rate Generator Block Diagram

Tx

TMST

TMST = 0

TMST = 1

SCKT

Rx

RMST

RMST = 0

RMST = 1

SCKR

Divider

Divide By 1

or 

Divide By 8

Divide By 1

To

Divide By 256

Prescale

PSR

PM0–PM7

RClock

TClock

F

OSC

Internal Clock

Divide

By 2

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