8-26
DSP56309UM/D MOTOROLA
Serial Communication Interface (SCI)
Operating Modes
8.4.4
Preamble, Break, and Data Transmission Priority
Two or three transmission commands can be set simultaneously:
1. A preamble (TE is set.)
2. A break (SBK is set or is cleared.)
3. There is data for transmission (TDRE is cleared.)
After the current character transmission, if two or more of these commands are set, the
transmitter executes them in the following order:
1. Preamble
2. Break
3. Data
8.4.5
SCI Exceptions
The SCI can cause five different exceptions in the DSP. These exceptions are as follows
(ordered from the highest to the lowest priority):
1. SCI receive data with exception status is caused by receive data register full with
a receiver error (parity, framing, or overrun error). Clearing the pending interrupt
is done by reading the SCI status register, followed by a read of SRX. A long
interrupt service routine should be used to handle the error condition. This
interrupt is enabled by SCR bit 16 (REIE).
2. SCI receive data is caused by receive data register full. Reading SRX clears the
pending interrupt. This error-free interrupt can use a fast interrupt service routine
for minimum overhead. This interrupt is enabled by SCR bit 11 (RIE).
3. SCI transmit data is caused by transmit data register empty. Writing STX clears
the pending interrupt. This error-free interrupt can use a fast interrupt service
routine for minimum overhead. This interrupt is enabled by SCR bit 12 (TIE).
4. SCI idle line is caused by the receive line entering the idle state (10 or 11 bits of
1s). This interrupt is latched and then automatically reset when the interrupt is
accepted. This interrupt is enabled by SCR bit 10 (ILIE).
5. SCI timer is caused by the baud rate counter reaching zero. This interrupt is
automatically reset when the interrupt is accepted. This interrupt is enabled by
SCR bit 13 (TMIE).
Summary of Contents for DSP56309
Page 25: ...xxii DSP56309UM D MOTOROLA Figure D 25 Port E Registers PCRE PRRE PDRE D 39 ...
Page 30: ...MOTOROLA DSP56309UM D 1 1 SECTION 1 DSP56309 OVERVIEW ...
Page 47: ...1 18 DSP56309UM D MOTOROLA DSP56309 Overview DSP56309 Architecture Overview ...
Page 48: ...MOTOROLA DSP56309UM D 2 1 SECTION 2 SIGNAL CONNECTION DESCRIPTIONS ...
Page 85: ...2 38 DSP56309UM D MOTOROLA Signal Connection Descriptions OnCE JTAG Interface ...
Page 86: ...MOTOROLA DSP56309UM D 3 1 SECTION 3 MEMORY CONFIGURATION ...
Page 104: ...MOTOROLA DSP56309UM D 4 1 SECTION 4 CORE CONFIGURATION ...
Page 124: ...MOTOROLA DSP56309UM D 5 1 SECTION 5 GENERAL PURPOSE I O ...
Page 125: ...5 2 DSP56309UM D MOTOROLA General Purpose I O 5 1 INTRODUCTION 5 3 5 2 PROGRAMMING MODEL 5 3 ...
Page 128: ...MOTOROLA DSP56309UM D 6 1 SECTION 6 HOST INTERFACE HI08 ...
Page 166: ...MOTOROLA DSP56309UM D 7 1 SECTION 7 ENHANCED SYNCHRONOUS SERIAL INTERFACE ESSI ...
Page 212: ...MOTOROLA DSP56309UM D 8 1 SECTION 8 SERIAL COMMUNICATION INTERFACE SCI ...
Page 241: ...8 30 DSP56309UM D MOTOROLA Serial Communication Interface SCI GPIO Signals and Registers ...
Page 242: ...MOTOROLA DSP56309UM D 9 1 SECTION 9 TRIPLE TIMER MODULE ...
Page 269: ...9 28 DSP56309UM D MOTOROLA Triple Timer Module Timer Operational Modes ...
Page 270: ...MOTOROLA DSP56309UM D 10 1 SECTION 10 ON CHIP EMULATION MODULE ...
Page 302: ...MOTOROLA DSP56309UM D 11 1 SECTION 11 JTAG PORT ...
Page 369: ...C 22 DSP56309UM D MOTOROLA DSP56309 BSDL Listing ...
Page 370: ...MOTOROLA DSP56309UM D D 1 APPENDIX D PROGRAMMING REFERENCE ...
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