Enhanced Synchronous Serial Interface (ESSI)
GPIO Signals and Registers
MOTOROLA
DSP56309UM/D 7-43
The SC[1:0] flags are available in synchronous mode only. Each flag can be separately
programmed.
Flag SC0 is enabled when transmitter 1 is disabled (TE1 = 0). The flagÕs 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). SC1Õs 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 respective SSISR IF[1:0] bits 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 on 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 DSP56309 to control data transmission by indirectly controlling the value of the
SC[1:0] flags.
7.6
GPIO SIGNALS AND REGISTERS
The GPIO functionality of an ESSI port (C, D) is controlled by three registers: port
control register (PCRC, PCRD), port direction register (PRRC, PRRD) and port data
register (PDRC, PDRD).
7.6.1
Port Control Register (PCR)
The read/write, 24-bit PCR controls the functionality of the ESSI GPIO signals. Each of
PC[5:0] bits controls the functionality of the corresponding port signal. When a PC[i] bit
is set, the corresponding port signal is configured as a ESSI signal. When a PC[i] bit is
cleared, the corresponding port signal is configured as a GPIO signal. Either a hardware
Summary of Contents for DSP56309
Page 25: ...xxii DSP56309UM D MOTOROLA Figure D 25 Port E Registers PCRE PRRE PDRE D 39 ...
Page 30: ...MOTOROLA DSP56309UM D 1 1 SECTION 1 DSP56309 OVERVIEW ...
Page 47: ...1 18 DSP56309UM D MOTOROLA DSP56309 Overview DSP56309 Architecture Overview ...
Page 48: ...MOTOROLA DSP56309UM D 2 1 SECTION 2 SIGNAL CONNECTION DESCRIPTIONS ...
Page 85: ...2 38 DSP56309UM D MOTOROLA Signal Connection Descriptions OnCE JTAG Interface ...
Page 86: ...MOTOROLA DSP56309UM D 3 1 SECTION 3 MEMORY CONFIGURATION ...
Page 104: ...MOTOROLA DSP56309UM D 4 1 SECTION 4 CORE CONFIGURATION ...
Page 124: ...MOTOROLA DSP56309UM D 5 1 SECTION 5 GENERAL PURPOSE I O ...
Page 125: ...5 2 DSP56309UM D MOTOROLA General Purpose I O 5 1 INTRODUCTION 5 3 5 2 PROGRAMMING MODEL 5 3 ...
Page 128: ...MOTOROLA DSP56309UM D 6 1 SECTION 6 HOST INTERFACE HI08 ...
Page 166: ...MOTOROLA DSP56309UM D 7 1 SECTION 7 ENHANCED SYNCHRONOUS SERIAL INTERFACE ESSI ...
Page 212: ...MOTOROLA DSP56309UM D 8 1 SECTION 8 SERIAL COMMUNICATION INTERFACE SCI ...
Page 241: ...8 30 DSP56309UM D MOTOROLA Serial Communication Interface SCI GPIO Signals and Registers ...
Page 242: ...MOTOROLA DSP56309UM D 9 1 SECTION 9 TRIPLE TIMER MODULE ...
Page 269: ...9 28 DSP56309UM D MOTOROLA Triple Timer Module Timer Operational Modes ...
Page 270: ...MOTOROLA DSP56309UM D 10 1 SECTION 10 ON CHIP EMULATION MODULE ...
Page 302: ...MOTOROLA DSP56309UM D 11 1 SECTION 11 JTAG PORT ...
Page 369: ...C 22 DSP56309UM D MOTOROLA DSP56309 BSDL Listing ...
Page 370: ...MOTOROLA DSP56309UM D D 1 APPENDIX D PROGRAMMING REFERENCE ...
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