Signal/Connection Descriptions
External Memory Expansion Port (Port A)
MOTOROLA
DSP56309UM/D 2-13
BB
Input/
Output
Input
Bus Busy
ÑBB is a bidirectional active-low
input/output and must be asserted and deasserted
synchronous to CLKOUT. BB indicates that the bus
is active. Only after BB is deasserted can the pending
bus master become the bus master (and then assert
the signal again). The bus master can keep BB
asserted after ceasing bus activity regardless of
whether BR is asserted or deasserted. This is called
Òbus parkingÓ and allows the current bus master to
reuse the bus without rearbitration until another
device requires the bus. The deassertion of BB is
done by an Òactive pull-upÓ method (i.e., BB is
driven high and then released and held high by an
external pull-up resistor).
BB requires an external pull-up resistor.
CAS
Output
Tri-stated
Column Address Strobe
ÑWhen the DSP is the bus
master, CAS is an active-low output used by DRAM
to strobe the column address. Otherwise, if the Bus
Mastership Enable (BME) bit in the DRAM Control
Register is cleared, the signal is tri-stated.
BCLK
Output
Tri-stated
Bus Clock
ÑWhen the DSP is the bus master, BCLK
is an active-high output. BCLK is active as a
sampling signal when the program address tracing
mode is enabled (by setting the ATE bit in the OMR).
When BCLK is active and synchronized to CLKOUT
by the internal PLL, BCLK precedes CLKOUT by 1/4
of a clock cycle. The BCLK rising edge can be used to
sample the internal program memory access on the
A0ÐA23 address lines.
BCLK
Output
Tri-stated
Bus Clock Not
ÑWhen the DSP is the bus master,
BCLK is an active-low output and is the inverse of
the BCLK signal. Otherwise, the signal is tri-stated.
Table 2-8
External Bus Control Signals (Continued)
Signal
Name
Type
State
During
Reset
Signal Description
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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