I/O Signals
8
-4
DSP56303 User’s Manual
To enable SCI interrupts, program the SCI control registers before any of the SCI signals are
programmed as SCI functions. In this case, only one transmit interrupt can be generated
because the Transmit Data Register is empty. The timer and timer interrupt operate regardless
of how the SCI pins are configured, either as SCI or GPIO.
8.2.1
Receive Data (RXD)
This input signal receives byte-oriented serial data and transfers the data to the SCI receive
shift register. Asynchronous input data is sampled on the positive edge of the receive clock (1
×
SCLK
) if the SCI Clock Polarity (SCKP) bit is cleared.
RXD
can be configured as a GPIO
signal (
PE0
) when the SCI
RXD
function is not in use.
8.2.2
Transmit Data (TXD)
This output signal transmits serial data from the SCI transmit shift register. Data changes on
the negative edge of the asynchronous transmit clock (
SCLK
) if SCKP is cleared. This output
is stable on the positive edge of the transmit clock.
TXD
can be programmed as a GPIO signal
(
PE1
) when the SCI
TXD
function is not in use.
8.2.3
SCI Serial Clock (SCLK)
This bidirectional signal provides an input or output clock from which the transmit and/or
receive baud rate is derived in Asynchronous mode and from which data is transferred in
Synchronous mode.
SCLK
can be programmed as a GPIO signal (
PE2
) when the SCI
SCLK
function is not in use. This signal can be programmed as
PE2
when data is being transmitted
on
TXD
, since the clock does not need to be transmitted in Asynchronous mode. Because
SCLK
is independent of SCI data I/O, there is no connection between programming the
PE2
signal as
SCLK
and data coming out the
TXD
signal.
Содержание DSP56303
Страница 1: ...DSP56303 User s Manual 24 Bit Digital Signal Processor DSP56303UM AD Revision 1 January 2001 ...
Страница 52: ...JTAG OnCE Interface 2 22 DSP56303 User s Manual ...
Страница 114: ...General Purpose Input Output GPIO 5 10 DSP56303 User s Manual ...
Страница 212: ...GPIO Signals and Registers 8 26 DSP56303 User s Manual ...
Страница 268: ...Interrupt Equates A 22 DSP56303 User s Manual ...
Страница 306: ...Programming Sheets B 38 DSP56303 User s Manual ...
Страница 320: ...Index 14 DSP56303 User s Manual ...