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DSP56305 User’s Manual
MOTOROLA
Enhanced Synchronous Serial Interface (ESSI)
GPIO/ESSI Selection and GPIO Usage
7.5.4
ESSI Flag Usage
Two ESSI signals (SC[1:0]) are available for use as serial I/O flags. Their operation is
controlled by the SYN, SCD[1:0], SSC1, and TE[2:1] bits in the CRB/CRA.The control bits
OF[1:0] and status bits IF[1:0] are double-buffered to/from SC[1:0]. Double-buffering the
flags keeps the flags in sync with TX and RX.
The SC[1:0] flags are available in the Synchronous mode only. Each flag can be
separately programmed.
Flag SC0 is enabled when transmitter 1 is disabled (TE1 = 0). The flag’s direction is
selected by the SCD0 bit. When SCD0 is set, SC0 is configured as output. When SCD0 is
cleared, SC0 is configured as input.
Similarly, the SC1 flag is enabled when transmitter 2 is disabled (TE2 = 0) and the SC1
signal is not configured as transmitter drive enable (Bit SSC1 = 0). SC1’s direction is
selected by the SCD1 bit. When SCD1 is set, SC1 is an output flag. When SCD1 is cleared,
SC1 is an input flag.
When programmed as input flags, the value of the SC[1:0] bits are latched at the same
time as the first bit of the receive data word is sampled. Once the input has been latched,
the signal on the input flag signal (SC0 and SC1) can change without affecting the input
flag. The value of SC[1:0] does not change until the first bit of the next data word is
received. When the received data word is latched by RX, the latched values of SC[1:0] are
latched by the SSISR IF[1:0] bits respectively, and can be read by software.
When programed as output flags, the value of the SC[1:0] bits is taken from the value of
the OF[1:0] bits. The value of the OF[1:0] bits is latched when the contents of TX are
transferred to the Transmit Shift Register. The value of SC[1:0] is stable from the time the
first bit of the transmit data word is transmitted until the first bit of the next transmit
data word is transmitted. The OF[1:0] values can be set directly by software. This allows
the DSP56305 to control data transmission by indirectly controlling the value of the
SC[1:0] flags.
7.6
GPIO/ESSI SELECTION AND GPIO USAGE
The GPIO functionality of an ESSI port (ESSI0 is Port C, ESSI1 is Port D) is controlled by
three registers: Port Control Register (PCRC, PCRD), Port Direction Register (PRRC,
PRRD) and Port Data Register (PDRC, PDRD). After a hardware reset, all Port C and
Port D pins are configured as GPIO inputs.
Summary of Contents for DSP56305
Page 34: ...xxxii DSP56305 User s Manual MOTOROLA ...
Page 40: ...xxxvi DSP56305 User s Manual MOTOROLA ...
Page 41: ...MOTOROLA DSP56305 User s Manual 1 1 SECTION 1 DSP56305 OVERVIEW ...
Page 58: ...1 18 DSP56305 User s Manual MOTOROLA DSP56305 Overview DSP56305 Architecture Overview ...
Page 59: ...MOTOROLA DSP56305 User s Manual 2 1 SECTION 2 SIGNAL CONNECTION DESCRIPTIONS ...
Page 98: ...2 40 DSP56305 User s Manual MOTOROLA Signal Connection Descriptions JTAG OnCE Interface ...
Page 99: ...MOTOROLA DSP56305 User s Manual 3 1 SECTION 3 MEMORY CONFIGURATION ...
Page 119: ...MOTOROLA DSP56305 User s Manual 4 1 SECTION 4 CORE CONFIGURATION ...
Page 144: ...4 26 DSP56305 User s Manual MOTOROLA Core Configuration JTAG Boundary Scan Register BSR ...
Page 145: ...MOTOROLA DSP56305 User s Manual 5 1 SECTION 5 GENERAL PURPOSE I O ...
Page 149: ...HOST INTERFACE HI32 MOTOROLA DSP56305 User s Manual 6 1 SECTION 6 HOST INTERFACE HI32 ...
Page 150: ...6 2 DSP56305 User s Manual MOTOROLA HOST INTERFACE HI32 ...
Page 259: ...MOTOROLA DSP56305 User s Manual 7 1 SECTION 7 ENHANCED SYNCHRONOUS SERIAL INTERFACE ESSI ...
Page 315: ...MOTOROLA DSP56305 User s Manual 8 1 SECTION 8 SERIAL COMMUNICATION INTERFACE SCI ...
Page 347: ...MOTOROLA DSP56305 User s Manual 9 1 SECTION 9 TIMER EVENT COUNTER ...
Page 376: ...9 30 DSP56305 User s Manual MOTOROLA Timer Event Counter Timer Modes of Operation ...
Page 377: ...MOTOROLA DSP56305 User s Manual 10 1 SECTION 10 ON CHIP EMULATION MODULE ...
Page 411: ...MOTOROLA DSP56305 User s Manual 11 1 SECTION 11 JTAG PORT ...
Page 430: ...11 20 DSP56305 User s Manual MOTOROLA JTAG Port DSP56305 Boundary Scan Register ...
Page 431: ...Filter Co Processor MOTOROLA DSP56305 User s Manual 12 1 SECTION 12 FILTER CO PROCESSOR ...
Page 471: ...VITERBI CO PROCESSOR MOTOROLA DSP56305 User s Manual 13 1 SECTION 13 VITERBI CO PROCESSOR ...
Page 522: ...13 52 DSP56305 User s Manual MOTOROLA VITERBI CO PROCESSOR References ...
Page 554: ...14 32 DSP56305 User s Manual MOTOROLA CYCLIC CODE CO PROCESSOR Configuration Examples ...
Page 555: ...MOTOROLA DSP56305 User s Manual A 1 APPENDIX A BOOTSTRAP CODE ...
Page 568: ...A 14 DSP56305 User s Manual MOTOROLA Bootstrap Code ...
Page 569: ...Equates MOTOROLA DSP56305 User s Manual B 1 APPENDIX B EQUATES ...
Page 589: ...MOTOROLA DSP56305 User s Manual C 1 APPENDIX C JTAG BSDL ...
Page 590: ...C 2 DSP56305 User s Manual MOTOROLA JTAG BSDL ...
Page 600: ...C 12 DSP56305 User s Manual MOTOROLA JTAG BSDL ...
Page 601: ...MOTOROLA DSP56305 User s Manual D 1 APPENDIX D PROGRAMMING REFERENCE ...
Page 602: ...D 2 DSP56305 User s Manual MOTOROLA PROGRAMMING REFERENCE ...
Page 661: ...Y MOTOROLA DSP56305 User s Manual Index 11 ...
Page 662: ...Y Index 12 DSP56305 User s Manual MOTOROLA ...