Motorola DSP56301 - Manual (Page 199)

Enhanced Synchronous Serial Interface (ESSI) 7 -1
Chapter 7
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
DSP56301: 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.
Figure 7-1. ESSI Block Diagram
RSMA
RSMB
TSMA
TSMB
SSISR
RX
RX SHIFT REG
TX0 SHIFT REG
TSR
RCLK
TX0
CRB
CRA
SRD
STD
TCLK
SC2
SCK Clock/Frame Sync Generators and Control Logic
Interrupts
TX1 SHIFT REG
TX1
SC0
TX2 SHIFT
TX2
SC1
GDB
DDB