Motorola DSP56012 6.2.3 SAI Transmit Section Overview

6-6 DSP56012 User’s Manual MOTOROLA
Serial Audio Interface
Serial Audio Interface Internal Architecture
6.2.3 SAI Transmit Section Overview
The transmit section contains three transmitters and consists of a 16-bit
control/status register, three 24-bit shift registers, and three 24-bit data registers.
These three transmitters are controlled by the same control mechanism, therefore, the
bit clock, word select line, and all control signals generated in the transmit section
equally affect all three transmitters. The transmit section can be configured as a
master driving its bit clock and word select lines from the internal baud-rate
generator, or as a slave receiving these signals from an external source. Each of the
three transmitters can be enabled separately. When a transmitter is disabled, its
associated Serial Data Out (SDO) pin goes to high level. When all transmitters are
disabled, the transmit controller becomes idle, the status bits TRDE and TLDE are
cleared, and the transmit section external pins, Word Select Transmit (WST) and
Serial Clock Transmit (SCKT), are tri-stated. The transmitter section is illustrated in
Figure 6-3.