Datasheet

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