Essi; Sci - Motorola DSP56303 User Manual

1.8.3

ESSI

The DSP56303 provides two independent and identical ESSIs. Each ESSI has a full-duplex
serial port for communication with a variety of serial devices, including one or more
industry-standard codecs, other DSPs, microprocessors, and peripherals that implement the
Motorola SPI. The ESSI consists of independent transmitter and receiver sections and a
common ESSI clock generator. ESSI capabilities include the following:
Independent (asynchronous) or shared (synchronous) transmit and receive sections
with separate or shared internal/external clocks and frame syncs
Normal mode operation using frame sync
Network mode operation with as many as 32 time slots
Programmable word length (8, 12, or 16 bits)
Program options for frame synchronization and clock generation
One receiver and three transmitters per ESSI
1.8.4

SCI

The SCI provides a full-duplex port for serial communication with other DSPs,
microprocessors, or peripherals such as modems. The SCI interfaces without additional logic
to peripherals that use TTL-level signals. With a small amount of additional logic, the SCI can
connect to peripheral interfaces that have non-TTL level signals, such as the RS-232C,
RS-422, etc. This interface uses three dedicated signals: transmit data, receive data, and SCI
serial clock. It supports industry-standard asynchronous bit rates and protocols, as well as
high-speed synchronous data transmission (up to 12.5 Mbps for a 100 MHz clock). SCI
asynchronous protocols include a multidrop mode for master/slave operation with wakeup on
idle line and wakeup on address bit capability. This mode allows the DSP56303 to share a
single serial line efficiently with other peripherals.
Separate SCI transmit and receive sections can operate asynchronously with respect to each
other. A programmable baud-rate generator provides the transmit and receive clocks. An
enable vector and an interrupt vector allow the baud-rate generator to function as a
general-purpose timer when the SCI is not using it or when the interrupt timing is the same as
that used by the SCI.
Overview
Peripherals
1-13