2-15
2.5 Direct Memory Access
There are two 82C37A equivalent Direct Memory Access Controllers (DMACs) contained in the SI
T9901. Direct Memory Access (DMA) operation allows high speed data transfers between memory
and I/O devices without the processor’s intervention. Seven DMA channels are defined in Table
2-3.
Table 2-3 DMA channel assignment
DMAC 1 contains channels 0 through 3. These channels transfer data as bytes (8 bits) between the
I/Os and the T2200SX working memory in 64KB blocks.
DMAC 2 contains channels 4 through 7. Channel 4 is used to cascade channels 0 through 3 to the
Central Processor. Channels 5 through 7 transfer data as words (16 bits) between the I/Os and
working memory in 128KB blocks. Channels 5 through 7 cannot transfer data on odd byte bound-
aries.
DMAC
Channel
Assigned to:
1
0
(Not used)
1
(Reserved)
2
FDD
3
(Reserved)
2
4
Cascade for DMAC 1
5
(Reserved)
6
(Reserved)
7
(Not used)
Содержание T-Series T2200sx
Страница 1: ...1 1 Chapter 1 Hardware Overview ...
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Страница 17: ...2 1 Chapter 2 Operational Overview ...
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Страница 42: ...2 26 2 13 Connectors Appendix B contains the pin assignments for the connectors within the T2200SX ...
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Страница 169: ...6 1 Chapter 6 Reassembly Procedures ...
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Страница 191: ...App 1 Appendices ...
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Страница 195: ...App 5 Appendix A System Board Layout A 1 System Board FSTFGx ICs Figure A 1 System board FSTFGx ICs front A D D C B ...
Страница 196: ...App 6 Figure A 2 System board FSTFGx ICs back G G G G E F J H I K ...
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Страница 199: ...App 9 A 2 System Board FSTFGx Connectors Figure A 3 System board FSTFGx connectors front M G I D B R K L L H N J O C F ...
Страница 200: ...App 10 Figure A 4 System board FSTFGx connectors back E A P Q ...
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Страница 203: ...App 13 A 3 System Board FSTFGx OSCs Figure A 5 System board FSTFGx OSCs front F G H E ...
Страница 204: ...App 14 Figure A 6 System board FSTFGx OSCs back A B C D ...
Страница 215: ...App 25 Appendix C ASCII Character Codes Table C 1 ASCII character codes ...
Страница 222: ...App 32 E 3 German Keyboard Figure E 3 German keyboard E 4 French Keyboard Figure E 4 French keyboard ...