211
32072H–AVR32–10/2012
AT32UC3A3
15.6.9.3
Page mode restriction
The page mode is not compatible with the use of the NWAIT signal. Using the page mode and
the NWAIT signal may lead to unpredictable behavior.
15.6.9.4
Sequential and non-sequential accesses
If the chip select and the MSB of addresses as defined in
are identical,
then the current access lies in the same page as the previous one, and no page break occurs.
Using this information, all data within the same page, sequential or not sequential, are accessed
with a minimum access time (t
sa
).
illustrates access to an 8-bit mem-
ory device in page mode, with 8-byte pages. Access to D1 causes a page access with a long
access time (t
pa
). Accesses to D3 and D7, though they are not sequential accesses, only require
a short access time (t
sa
).
If the MSB of addresses are different, the SMC performs the access of a new page. In the same
way, if the chip select is different from the previous access, a page break occurs. If two sequen-
tial accesses are made to the page mode memory, but separated by an other internal or external
peripheral access, a page break occurs on the second access because the chip select of the
device was deasserted between both accesses.
Figure 15-34. Access to Non-sequential Data within the Same Page
CLK_SMC
A[AD_MSB:3]
A[2], A1, A0
NCS
NRD
D[7:0]
A1
Page address
A3
A7
D1
D3
D7
NCSRDPULSE
NRDPULSE
NRDPULSE
Содержание AT32UC3A3128
Страница 61: ...61 32072H AVR32 10 2012 AT32UC3A3 PLLEN PLL Enable 0 PLL is disabled 1 PLL is enabled...
Страница 260: ...260 32072H AVR32 10 2012 AT32UC3A3 5 2560 3071 6 3072 3583 7 3584 4095 Bit Index n Sector Boundaries...
Страница 592: ...592 32072H AVR32 10 2012 AT32UC3A3 Manchester Configuration Register on page 614...
Страница 989: ...989 32072H AVR32 10 2012 AT32UC3A3 37 2 Package Drawings Figure 37 1 TFBGA 144 package drawing...
Страница 991: ...991 32072H AVR32 10 2012 AT32UC3A3 Figure 37 3 VFBGA 100 package drawing...