
204
to cause the external device to negate the
BREQ
and return the bus rights to the SH7040 Series.
Please note that if the external device does not return the bus rights within the time prescribed for
the DRAM refresh interval, this LSI will not be able to perform the refresh operation and the
DRAM contents cannot be guaranteed.
Figure 10.22 shows the bus right release procedure.
BREQ
= Low
SH704X
BREQ
accepted
Strobe pin:
high-level output
Address, data,
strobe pin:
high impedance
Bus right release
response
Bus right release status
External device
Bus right request
BACK
confirmation
Bus right acquisition
BACK
= Low
Figure 10.22 Bus Right Release Procedure
Содержание SH7041 Series
Страница 2: ......
Страница 6: ......
Страница 38: ...xvi ...
Страница 44: ...6 ...
Страница 46: ...8 ...
Страница 48: ...10 ...
Страница 82: ...44 ...
Страница 114: ...76 ...
Страница 118: ...80 ...
Страница 124: ...86 ...
Страница 170: ...132 ...
Страница 250: ...212 ...
Страница 492: ...454 ...
Страница 506: ...468 ...
Страница 604: ...566 ...
Страница 684: ...646 ...
Страница 706: ...668 ...
Страница 778: ...740 ...
Страница 780: ...742 ...
Страница 818: ...780 ...
Страница 850: ...812 ...
Страница 923: ...SH7040 SH7041 SH7042 SH7043 SH7044 SH7045 Group Hardware Manual REJ09B0044 0600O ...