CONNECTION WITH EXTERNAL DEVICES
7751 Group User’s Manual
12–19
12.4 Hold function
12.4.1 Operation description
_____
Judgment timing of the input level of the HOLD pin depends on the state using the bus. While the bus is
not in use, the judgment is performed at every falling of
φ
BIU
. While the bus is in use, the judgment timing
_____
depends on the bus cycle. Table 12.4.2 lists the judgment timing of the input level of the HOLD pin during
the used bus.
Additionally, when accessing word data beginning from an odd address with 2-bus cycle, the judgment is
performed only at the second bus cycle. (See Figure 12.4.1.)
When “L” level is detected at judgment of the input level, the microcomputer enters Hold state. (This is
called acceptance of Hold request.)
_____
When the Hold request is accepted,
φ
CPU
stops next rising of
φ
BIU
. At the same time, the HLDA pin’s level
_____
__
changes “H” to “L”. When 1 cycle of
φ
BIU
has passed after the level of HLDA pin becomes “L”, pins R/W,
___
BHE, and the external bus become floating state.
_____
In Hold state, the input level of the HOLD pin is judged at every falling of
φ
BIU
. Then, when “H” level is
_____
detected, the HLDA pin’s level changes “L” to “H” next rising of
φ
BIU
. When 1 cycle of
φ
BIU
has passed after
_____
the level of HLDA pin becomes “H”, the microcomputer terminates Hold state.
Figures 12.4.2 to 12.4.4 show timing of acceptance of Hold request and termination of Hold state.
Note:
φ
BIU
has a same polarity and a same frequency as the clock
φ
1
. However,
φ
BIU
stops by acceptance
of the Ready request, or executing the STP or WIT instruction. Accordingly, judgment of the input
_____
level of the HOLD pin is not performed during Ready state.
Clock
1
BIU
ALE
Reading
Writing
Judgment timing of input level to HOLD pin
No judge
Judge
Accessing word data with 2-bus cycle.
(Example of 2
access in low-speed running
)
E
A
A
A
W
A
W
Fig. 12.4.1 Judgment when accessing word data beginning from odd address with 2-bus cycle
Содержание 7700 FAMILY
Страница 2: ...MITSUBISHI 16 BIT SINGLE CHIP MICROCOMPUTER 7700 FAMILY 7751 SERIES 7751 Group User s Manual...
Страница 11: ...Table of Contents viii 7751 Group User s Manual MEMORANDUM...
Страница 12: ...CHAPTER 1 DESCRIPTION 1 1 Performance overview 1 2 Pin configuration 1 3 Pin description 1 4 Block diagram...
Страница 48: ...CHAPTER 3 INPUT OUTPUT PINS 3 1 Programmable I O ports 3 2 I O pins of internal peripheral devices...
Страница 157: ...TIMER B 6 28 7751 Group User s Manual 6 5 Pulse period pulse width measurement mode MEMORANDUM...
Страница 245: ...7751 Group User s Manual 8 36 A D CONVERTER Precautions when using A D converter MEMORANDUM...
Страница 246: ...CHAPTER 9 WATCHDOG TIMER 9 1 Block description 9 2 Operation description 9 3 Precautions when using watchdog timer...
Страница 254: ...CHAPTER 10 STOP MODE 10 1 Clock generating circuit 10 2 Operation description 10 3 Precautions for Stop mode...
Страница 260: ...CHAPTER 11 WAIT MODE 11 1 Clock generating circuit 11 2 Operation description 11 3 Precautions for Wait mode...
Страница 265: ...7751 Group User s Manual WAIT MODE 11 6 11 3 Precautions for Wait mode MEMORANDUM...
Страница 289: ...CONNECTION WITH EXTERNAL DEVICES 12 4 Hold function 7751 Group User s Manual 12 24 MEMORANDUM...
Страница 290: ...CHAPTER 13 RESET 13 1 Hardware reset 13 2 Software reset...
Страница 302: ...CHAPTER 14 CLOCK GENERATING CIRCUIT 14 1 Oscillation circuit example 14 2 Clock...
Страница 307: ...CLOCK GENERATING CIRCUIT 7751 Group User s Manual 14 6 14 2 Clock MEMORANDUM...
Страница 359: ...ELECTRICAL CHARACTERISTICS 7751 Group User s Manual 15 52 MEMORANDUM 15 15 Testing circuit for ports P0 to P8 1 and E...
Страница 360: ...CHAPTER 16 STANDARD CHARACTERISTICS 16 1 Standard characteristics...
Страница 365: ...STANDARD CHARACTERISTICS 16 1 Standard characteristics 7751 Group User s Manual 16 6 MEMORANDUM...
Страница 366: ...CHAPTER 17 APPLICATIONS 17 1 Memory expansion...
Страница 405: ...APPLICATIONS 7751 Group User s Manual 17 40 17 1 Memory expansion MEMORANDUM...
Страница 406: ...CHAPTER 18 PROM VERSION 18 1 EPROM mode 18 2 Usage precaution...
Страница 417: ...7751 Group User s Manual PROM VERSION 18 12 18 2 Usage precaution MEMORANDUM...
Страница 418: ...CHAPTER 19 FLASH MEMORY VERSION 19 1 Parallel input output mode 19 2 Serial input output mode...
Страница 451: ...FLASH MEMORY VERSION 7751 Group User s Manual 19 34 19 2 Serial input output mode MEMORANDUM...
Страница 483: ...APPENDIX 7751 Group User s Manual 20 32 Appendix 4 Package outlines Appendix 4 Package outlines 80P6N A...
Страница 484: ...APPENDIX 7751 Group User s Manual 20 33 Appendix 4 Package outlines 80D0...
Страница 489: ...APPENDIX 7751 Group User s Manual 20 38 Appendix 6 Hexadecimal instruction code table...
Страница 490: ...APPENDIX 7751 Group User s Manual 20 39 Appendix 6 Hexadecimal instruction code table...
Страница 491: ...APPENDIX 7751 Group User s Manual 20 40 Appendix 7 Machine instructions Appendix 7 Machine instructions...
Страница 492: ...APPENDIX 7751 Group User s Manual 20 41 Appendix 7 Machine instructions...
Страница 493: ...APPENDIX 7751 Group User s Manual 20 42 Appendix 7 Machine instructions...
Страница 494: ...APPENDIX 7751 Group User s Manual 20 43 Appendix 7 Machine instructions...
Страница 495: ...APPENDIX 7751 Group User s Manual 20 44 Appendix 7 Machine instructions...
Страница 496: ...APPENDIX 7751 Group User s Manual 20 45 Appendix 7 Machine instructions...
Страница 497: ...APPENDIX 7751 Group User s Manual 20 46 Appendix 7 Machine instructions...
Страница 498: ...APPENDIX 7751 Group User s Manual 20 47 Appendix 7 Machine instructions...
Страница 499: ...APPENDIX 7751 Group User s Manual 20 48 Appendix 7 Machine instructions...
Страница 500: ...APPENDIX 7751 Group User s Manual 20 49 Appendix 7 Machine instructions...
Страница 501: ...APPENDIX 7751 Group User s Manual 20 50 Appendix 7 Machine instructions...
Страница 502: ...APPENDIX 7751 Group User s Manual 20 51 Appendix 7 Machine instructions...
Страница 503: ...APPENDIX 7751 Group User s Manual 20 52 Appendix 7 Machine instructions...
Страница 504: ...APPENDIX 7751 Group User s Manual 20 53 Appendix 7 Machine instructions...
Страница 505: ...APPENDIX 7751 Group User s Manual 20 54 Appendix 7 Machine instructions...
Страница 506: ...APPENDIX 7751 Group User s Manual 20 55 Appendix 7 Machine instructions...
Страница 507: ...APPENDIX 7751 Group User s Manual 20 56 Appendix 7 Machine instructions...
Страница 508: ...APPENDIX 7751 Group User s Manual 20 57 Appendix 7 Machine instructions...
Страница 509: ...APPENDIX 7751 Group User s Manual 20 58 Appendix 7 Machine instructions...
Страница 510: ...APPENDIX 7751 Group User s Manual 20 59 Appendix 7 Machine instructions...
Страница 511: ...APPENDIX 7751 Group User s Manual 20 60 Appendix 7 Machine instructions...
Страница 535: ...APPENDIX Appendix 9 Q A 7751 Group User s Manual 20 84 MEMORANDUM...
Страница 536: ...GLOSSARY...
Страница 539: ...GLOSSARY 7751 Group User s Manual 4 MEMORANDUM...