Section 6 Bus Controller (BSC)
Rev.2.00 Jun. 28, 2007 Page 216 of 666
REJ09B0311-0200
(3)
External Bus Release Function and Software Standby
In this LSI, internal bus master operation does not stop even while the bus is released, as long as
the program is running in on-chip RAM, etc., and no external access occurs. If a SLEEP
instruction to place the chip in software standby mode is executed while the external bus is
released, the transition to software standby mode is deferred and performed after the bus is
recovered.
Also, since clock oscillation halts in software standby mode, if the
BREQ
signal goes low in this
mode, indicating an external bus release request, the request cannot be answered until the chip has
recovered from the software standby mode.
Note that
BACK
and
BREQO
goes Hi-Z during software standby.
(4)
BREQO
Output Timing
When the BREQOE bit is set to 1 and the
BREQO
signal is output, both the
BREQO
and
BACK
signals may go low simultaneously.
This will occur if the next external access request occurs while internal bus arbitration is in
progress after the chip samples a low level of the
BREQ
signal.
Содержание H8SX/1650
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Страница 106: ...Section 4 Exception Handling Rev 2 00 Jun 28 2007 Page 84 of 666 REJ09B0311 0200...
Страница 142: ...Section 5 Interrupt Controller Rev 2 00 Jun 28 2007 Page 120 of 666 REJ09B0311 0200...
Страница 326: ...Section 8 I O Ports Rev 2 00 Jun 28 2007 Page 304 of 666 REJ09B0311 0200...
Страница 470: ...Section 12 Watchdog Timer WDT Rev 2 00 Jun 28 2007 Page 448 of 666 REJ09B0311 0200...
Страница 546: ...Section 13 Serial Communication Interface SCI Rev 2 00 Jun 28 2007 Page 524 of 666 REJ09B0311 0200...
Страница 566: ...Section 14 A D Converter Rev 2 00 Jun 28 2007 Page 544 of 666 REJ09B0311 0200...
Страница 574: ...Section 16 RAM Rev 2 00 Jun 28 2007 Page 552 of 666 REJ09B0311 0200...
Страница 584: ...Section 17 Clock Pulse Generator Rev 2 00 Jun 28 2007 Page 562 of 666 REJ09B0311 0200...
Страница 638: ...Section 19 List of Registers Rev 2 00 Jun 28 2007 Page 616 of 666 REJ09B0311 0200...
Страница 668: ...Section 20 Electrical Characteristics Rev 2 00 Jun 28 2007 Page 646 of 666 REJ09B0311 0200...
Страница 676: ...Appendix Rev 2 00 Jun 28 2007 Page 654 of 666 REJ09B0311 0200...
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