DSP56303 FREESCALE [Freescale Semiconductor, Inc], DSP56303 Datasheet - Page 133

• Manufacturer Part Number: DSP56303
• Manufacturer: FREESCALE [Freescale Semiconductor, Inc]

Enhanced Synchronous Serial Interface
(ESSI)
The ESSI 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. The ESSI consists of independent transmitter and receiver sections and a common
ESSI clock generator. There are two independent and identical ESSIs in the DSP56303: ESSI0
and ESSI1. For simplicity, a single generic ESSI is described here. The ESSI block diagram is
shown in Figure 7-1. This interface is synchronous because all serial transfers are synchronized
to one clock.
This synchronous interface should not be confused with the asynchronous channels mode of the
ESSI, in which separate clocks are used for the receiver and transmitter. In that mode, the ESSI is
still a synchronous device because all transfers are synchronized to these clocks. Pin notations for
the generic ESSI refer to the analogous pin of ESSI0 (
Freescale Semiconductor
Interrupts
Clock/Frame Sync Generators and Control Logic
Figure 7-1. ESSI Block Diagram
DSP56303 User’s Manual, Rev. 2
RSMB
SSISR
RSMA
TSMB
TSMA
CRB
CRA
TSR
GDB
DDB
RCLK
TCLK
PCx
) and ESSI1 (
RX SHIFT REG
TX2 SHIFT
TX0 SHIFT REG
TX1 SHIFT REG
TX0
TX2
TX1
RX
PDx
STD
SC0
SC1
SC2
SCK
SRD
).
7
7-1