8-12
DSP56305 User’s Manual
MOTOROLA
Serial Communication Interface (SCI)
SCI Programming Model
8.3.1.8
Transmitter Enable (TE) SCR Bit 9
When TE is set, the transmitter is enabled. When TE is cleared, the transmitter completes
transmission of data in the SCI Transmit Data Shift Register, then the serial output is
forced high (i.e., idle). Data present in the SCI Transmit Data Register (STX) is not
transmitted. STX may be written and TDRE cleared, but the data is not transferred into
the shift register. TE does not inhibit TDRE or transmit interrupts. TE is cleared by
hardware and software reset.
Setting TE causes the transmitter to send a preamble of ten or eleven consecutive 1s
(depending on WDS). This procedure gives the programmer a convenient way to ensure
that the line goes idle before starting a new message. To force this separation of
messages by the minimum idle line time, the following sequence is recommended:
1. Write the last byte of the first message to STX.
2. Wait for TDRE to go high, indicating the last byte has been transferred to the
Transmit Shift Register.
3. Clear TE and set TE. This queues an idle line preamble to follow immediately the
transmission of the last character of the message (including the stop bit).
4. Write the first byte of the second message to STX.
In this sequence, if the first byte of the second message is not transferred to STX prior to
the finish of the preamble transmission, the transmit data line marks idle until STX is
finally written.
8.3.1.9
Idle Line Interrupt Enable (ILIE) SCR Bit 10
When ILIE is set, the SCI interrupt occurs when IDLE (SSR Bit 3) is set. When ILIE is
cleared, the IDLE interrupt is disabled. ILIE is cleared by hardware and software reset.
An internal flag, the Shift Register Idle Interrupt (SRIINT) flag, is the interrupt request to
the interrupt controller. SRIINT is not directly accessible to the user.
When a valid start bit has been received, an idle interrupt is generated if both IDLE and
ILIE are set. The idle interrupt acknowledge from the interrupt controller clears this
interrupt request. The idle interrupt is not asserted again until at least one character has
been received. The results are as follows:
1. The IDLE bit shows the real status of the receive line at all times.
2. An idle interrupt is generated once for each idle state, no matter how long the idle
state lasts.
Summary of Contents for DSP56305
Page 34: ...xxxii DSP56305 User s Manual MOTOROLA ...
Page 40: ...xxxvi DSP56305 User s Manual MOTOROLA ...
Page 41: ...MOTOROLA DSP56305 User s Manual 1 1 SECTION 1 DSP56305 OVERVIEW ...
Page 58: ...1 18 DSP56305 User s Manual MOTOROLA DSP56305 Overview DSP56305 Architecture Overview ...
Page 59: ...MOTOROLA DSP56305 User s Manual 2 1 SECTION 2 SIGNAL CONNECTION DESCRIPTIONS ...
Page 98: ...2 40 DSP56305 User s Manual MOTOROLA Signal Connection Descriptions JTAG OnCE Interface ...
Page 99: ...MOTOROLA DSP56305 User s Manual 3 1 SECTION 3 MEMORY CONFIGURATION ...
Page 119: ...MOTOROLA DSP56305 User s Manual 4 1 SECTION 4 CORE CONFIGURATION ...
Page 144: ...4 26 DSP56305 User s Manual MOTOROLA Core Configuration JTAG Boundary Scan Register BSR ...
Page 145: ...MOTOROLA DSP56305 User s Manual 5 1 SECTION 5 GENERAL PURPOSE I O ...
Page 149: ...HOST INTERFACE HI32 MOTOROLA DSP56305 User s Manual 6 1 SECTION 6 HOST INTERFACE HI32 ...
Page 150: ...6 2 DSP56305 User s Manual MOTOROLA HOST INTERFACE HI32 ...
Page 259: ...MOTOROLA DSP56305 User s Manual 7 1 SECTION 7 ENHANCED SYNCHRONOUS SERIAL INTERFACE ESSI ...
Page 315: ...MOTOROLA DSP56305 User s Manual 8 1 SECTION 8 SERIAL COMMUNICATION INTERFACE SCI ...
Page 347: ...MOTOROLA DSP56305 User s Manual 9 1 SECTION 9 TIMER EVENT COUNTER ...
Page 376: ...9 30 DSP56305 User s Manual MOTOROLA Timer Event Counter Timer Modes of Operation ...
Page 377: ...MOTOROLA DSP56305 User s Manual 10 1 SECTION 10 ON CHIP EMULATION MODULE ...
Page 411: ...MOTOROLA DSP56305 User s Manual 11 1 SECTION 11 JTAG PORT ...
Page 430: ...11 20 DSP56305 User s Manual MOTOROLA JTAG Port DSP56305 Boundary Scan Register ...
Page 431: ...Filter Co Processor MOTOROLA DSP56305 User s Manual 12 1 SECTION 12 FILTER CO PROCESSOR ...
Page 471: ...VITERBI CO PROCESSOR MOTOROLA DSP56305 User s Manual 13 1 SECTION 13 VITERBI CO PROCESSOR ...
Page 522: ...13 52 DSP56305 User s Manual MOTOROLA VITERBI CO PROCESSOR References ...
Page 554: ...14 32 DSP56305 User s Manual MOTOROLA CYCLIC CODE CO PROCESSOR Configuration Examples ...
Page 555: ...MOTOROLA DSP56305 User s Manual A 1 APPENDIX A BOOTSTRAP CODE ...
Page 568: ...A 14 DSP56305 User s Manual MOTOROLA Bootstrap Code ...
Page 569: ...Equates MOTOROLA DSP56305 User s Manual B 1 APPENDIX B EQUATES ...
Page 589: ...MOTOROLA DSP56305 User s Manual C 1 APPENDIX C JTAG BSDL ...
Page 590: ...C 2 DSP56305 User s Manual MOTOROLA JTAG BSDL ...
Page 600: ...C 12 DSP56305 User s Manual MOTOROLA JTAG BSDL ...
Page 601: ...MOTOROLA DSP56305 User s Manual D 1 APPENDIX D PROGRAMMING REFERENCE ...
Page 602: ...D 2 DSP56305 User s Manual MOTOROLA PROGRAMMING REFERENCE ...
Page 661: ...Y MOTOROLA DSP56305 User s Manual Index 11 ...
Page 662: ...Y Index 12 DSP56305 User s Manual MOTOROLA ...