Freescale Semiconductor DSP56366 - Manual (Page 151)

DSP56366 24-Bit Digital Signal Processor User Manual, Rev. 4
Freescale Semiconductor 8-1
8 Enhanced Serial AUDIO Interface (ESAI)
8.1 Introduction
The Enhanced Serial Audio Interface (ESAI) provides a full-duplex serial port for serial communication
with a variety of serial devices including one or more industry-standard codecs, other DSPs,
microprocessors, and peripherals which implement the Freescale SPI serial protocol. The ESAI consists
of independent transmitter and receiver sections, each section with its own clock generator. It is a superset
of the 56300 Family ESSI peripheral and of the 56000 Family SAI peripheral.
NOTE
The DSP56366 has two ESAI modules. This section describes the ESAI,
and Section 9 describes the ESAI_1. The ESAI and ESAI_1 share 4 data
pins. This is described in the ESAI_1 section.
The ESAI block diagram is shown in Figure 8-1 . The ESAI is named synchronous because all serial
transfers are synchronized to a clock. Additional synchronization signals are used to delineate the word
frames. The normal mode of operation is used to transfer data at a periodic rate, one word per period. The
network mode is similar in that it is also intended for periodic transfers; however, it supports up to 32
words (time slots) per period. This mode can be used to build time division multiplexed (TDM) networks.
In contrast, the on-demand mode is intended for non-periodic transfers of data and to transfer data serially
at high speed when the data becomes available. This mode offers a subset of the SPI protocol.