Motorola DSP56301 - Manual (Page 57)

Serial Communications Interface (SCI)
Signals/Connections 2 -27
2.10 Serial Communications Interface (SCI)
The SCI provides a full duplex port for serial communication with other DSPs,
microprocessors, or peripherals such as modems. All SCI pins are 5 V tolerant.
2.11 Timers
The DSP56301 has three identical and independent timers. Each timer can use internal or
external clocking and either interrupt the DSP56301 after a specified number of events
(clocks) or signal an external device after counting a specific number of internal events. All
timer pins are 5 V tolerant.
Table 2-15. Serial Communication Interface
Signal Name Type
State During
Reset
Signal Description
RXD
PE0
Input
Input or Output
Input Serial Receive Data—Receives byte-oriented serial data
and transfers it to the SCI receive shift register.
Port E 0—The default configuration following reset is GPIO
input PE0. When configured as PE0, signal direction is
controlled through the SCI port directions register (PRR). The
signal can be configured as an SCI signal RXD through the
SCI port control register (PCR).
This signal has a weak keeper to maintain the last state even
if all drivers are tri-stated.
TXD
PE1
Output
Input or Output
Input Serial Transmit Data—Transmits data from the SCI transmit
data register.
Port E 1—The default configuration following reset is GPIO
input PE1. When configured as PE1, signal direction is
controlled through the SCI PRR. The signal can be
configured as an SCI signal TXD through the SCI PCR.
This signal has a weak keeper to maintain the last state even
if all drivers are tri-stated.
SCLK
PE2
Input/ Output
Input or Output
Input Serial Clock—Provides the input or output clock used by the
transmitter and/or the receiver.
Port E 2—The default configuration following reset is GPIO
input PE2. When configured as PE2, signal direction is
controlled through the SCI PRR. The signal can be
configured as an SCI signal SCLK through the SCI PCR.
This signal has a weak keeper to maintain the last state even
if all drivers are tri-stated.