Figure 7-3 Scn0 Pin Configuration; Serial Control Signal (Sc0) - Motorola DSP56305 User Manual

Enhanced Synchronous Serial Interface (ESSI)
ESSI Data and Control Signals
7.3.4

Serial Control Signal (SC0)

In ESSI0: SC00; In ESSI1: SC10
The function of this signal is determined by selecting either Synchronous or
Asynchronous mode (see Figure 7-3, Table 7-4, and Figure 7-15). In Asynchronous
mode, this signal is used for the receive clock I/O. In Synchronous mode, this signal is
used as the transmitter data out signal for Transmit Shift Register 1 or for serial flag I/O.
A typical application of serial flag I/O would be multiple device selection for addressing
in codec systems.
Synchronous
operation?
Use
transmitter
#1?
Pin
direction?
Input
SCn0
RX Clock
pin is...
Note: 1. "n" in SCn0 is ESSI (0 or 1)
2. TD1 = Transmit Data Signal 1
If SC0 is configured as a serial flag signal, its direction is determined by the Serial
Control Direction 0 (SCD0) bit in the ESSI Control Register B (CRB). When configured as
an output, its direction is determined by the value of the serial Output Flag 0 (OF0) bit in
the CRB.
7-8
Async
0
Mode
0 1
SCD0
Output
CRB
RX Clock

Figure 7-3 SCn0 Pin Configuration

DSP56305 User's Manual
SCn0 Pin
Sync
1
SYN
Mode
CRB
0
0
SCD0
Input
CRB
Flag 0 Flag 0
In Out
1
TE1
CRB
1
Output
TD1
Out
AA1457
MOTOROLA