2-12
DSP56309UM/D MOTOROLA
Signal/Connection Descriptions
External Memory Expansion Port (Port A)
BR
Output
Output
(deasserted)
Bus Request
ÑBR is an active-low output, never
tri-stated. BR is asserted when the DSP requests bus
mastership. BR is deasserted when the DSP no
longer needs the bus. BR can be asserted or
deasserted independent of whether the DSP56309 is
a bus master or a bus slave. Bus ÒparkingÓ allows BR
to be deasserted even though the DSP56309 is the
bus master; see the description of bus ÒparkingÓ in
the BB signal description. The bus request hole
(BRH) bit in the BCR allows BR to be asserted under
software control even though the DSP does not need
the bus. BR is typically sent to an external bus
arbitrator that controls the priority, parking, and
tenure of each master on the same external bus. BR is
only affected by DSP requests for the external bus,
never for the internal bus. During hardware reset,
BR is deasserted and the arbitration is reset to the
bus slave state.
BG
Input
Ignored
Input
Bus Grant
ÑBG is an active-low input. BG must be
asserted/deasserted synchronous to CLKOUT for
proper operation. BG is asserted by an external bus
arbitration circuit when the DSP56309 becomes the
next bus master. When BG is asserted, the DSP56309
must wait until BB is deasserted before taking bus
mastership. When BG is deasserted, bus mastership
is typically given up at the end of the current bus
cycle. This can occur in the middle of an instruction
that requires more than one external bus cycle for
execution.
Table 2-8
External Bus Control Signals (Continued)
Signal
Name
Type
State
During
Reset
Signal Description
Содержание DSP56309
Страница 25: ...xxii DSP56309UM D MOTOROLA Figure D 25 Port E Registers PCRE PRRE PDRE D 39 ...
Страница 30: ...MOTOROLA DSP56309UM D 1 1 SECTION 1 DSP56309 OVERVIEW ...
Страница 47: ...1 18 DSP56309UM D MOTOROLA DSP56309 Overview DSP56309 Architecture Overview ...
Страница 48: ...MOTOROLA DSP56309UM D 2 1 SECTION 2 SIGNAL CONNECTION DESCRIPTIONS ...
Страница 85: ...2 38 DSP56309UM D MOTOROLA Signal Connection Descriptions OnCE JTAG Interface ...
Страница 86: ...MOTOROLA DSP56309UM D 3 1 SECTION 3 MEMORY CONFIGURATION ...
Страница 104: ...MOTOROLA DSP56309UM D 4 1 SECTION 4 CORE CONFIGURATION ...
Страница 124: ...MOTOROLA DSP56309UM D 5 1 SECTION 5 GENERAL PURPOSE I O ...
Страница 125: ...5 2 DSP56309UM D MOTOROLA General Purpose I O 5 1 INTRODUCTION 5 3 5 2 PROGRAMMING MODEL 5 3 ...
Страница 128: ...MOTOROLA DSP56309UM D 6 1 SECTION 6 HOST INTERFACE HI08 ...
Страница 166: ...MOTOROLA DSP56309UM D 7 1 SECTION 7 ENHANCED SYNCHRONOUS SERIAL INTERFACE ESSI ...
Страница 212: ...MOTOROLA DSP56309UM D 8 1 SECTION 8 SERIAL COMMUNICATION INTERFACE SCI ...
Страница 241: ...8 30 DSP56309UM D MOTOROLA Serial Communication Interface SCI GPIO Signals and Registers ...
Страница 242: ...MOTOROLA DSP56309UM D 9 1 SECTION 9 TRIPLE TIMER MODULE ...
Страница 269: ...9 28 DSP56309UM D MOTOROLA Triple Timer Module Timer Operational Modes ...
Страница 270: ...MOTOROLA DSP56309UM D 10 1 SECTION 10 ON CHIP EMULATION MODULE ...
Страница 302: ...MOTOROLA DSP56309UM D 11 1 SECTION 11 JTAG PORT ...
Страница 369: ...C 22 DSP56309UM D MOTOROLA DSP56309 BSDL Listing ...
Страница 370: ...MOTOROLA DSP56309UM D D 1 APPENDIX D PROGRAMMING REFERENCE ...
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