
2-16
DSP56853/854/855/857/858 User’s Manual
MOTOROLA
Preliminary
Power, Ground and Peripheral Signals
2
SC01
(GPIOC4)
Input / Output
Input / Output
ESSI Serial Control Pin 1—The function of this
pin is determined by the selection of either
synchronous or asynchronous mode. for
asynchronous mode, this pin is the receiver frame
sync I/O. For synchronous mode, this pin is used
either for transmitter 2 output or for serial I/O flag
1.
Port C GPIO 4—This is a General Purpose I/O pin
when the ESSI is not in use.
11
1
SC02
(GPIOC5)
Input / Output
Input / Output
ESSI Serial Control Pin 2—This pin is used for
frame sync I/O. SC02 is the frame sync for both
the transmitter and receiver in synchronous mode
and for the transmitter only in asynchronous more.
When configured as an output, this pin is the
internally generated frame sync signal. When
configured as an input, this pin receives an
external sync signal for the transmitter, and the
receiver in the synchronous operation.
Port C GPIO 5—This is a General Purpose I/O pin
capable of being independently programmed as an
input or output pin.
11
1
Table 2-12. Enhanced Synchronous Serial Interface 1
Signal Name
Signal Type
853
Pins
854
Pins
855
Pins
857
Pins
858
Pins
STD1
(GPIOD0)
Output(Z)
Input / Output
ESSI Transmit Data (STD1)—This output pin
transmits serial data from the ESSI Transmitter
Shift Register.
Port D GPIO 0—This is a General Purpose I/O pin
available when the ESSI is not in use.
——
—
11
SRD1
(GPIOD1)
Input
Input / Output
ESSI Receive Data (SRD1)—This input pin
receives serial data and transfers the data to the
ESSI Receive Shift Register.
Port D GPIO 1—This is a General Purpose I/O pin
available when the ESSI is not in use.
——
—
11
SCK1
(GPIOD2)
Input / Output
Input / Output
ESSI Serial Clock (SCK1)—This bidirectional pin
provides the serial bit rate clock for the transmit
section of the ESSI. The clock signal can be
continuous or gated and can be used by both the
transmitter and receiver in synchronous mode.
Port D GPIO 2—This is a General Purpose I/O pin
available when the ESSI is not in use.
——
—
11
Table 2-11. Enhanced Synchronous Serial Interface 0 (Continued)
Signal Name
Signal Type
853
Pins
854
Pins
855
Pins
857
Pins
858
Pins