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6174B–ATARM–07-Nov-05
AT91FR40162S Preliminary
cycles and is released at the completion of the cycle. The open-drain connection allows for OR-
tying of several devices to the same RDY/BUSY line. See
Table 11-1, “Status Bit Table,” on
for more details.
11.3.8
Common Flash Interface (CFI)
CFI is a published, standardized data structure that may be read from a flash device. CFI allows
system software to query the installed device to determine the configurations, various electrical
and timing parameters, and functions supported by the device. CFI is used to allow the system
to learn how to interface to the flash device most optimally. The two primary benefits of using
CFI are ease of upgrading and second source availability. The command to enter the CFI Query
mode is a one-bus cycle command which requires writing data 98h to address 55h. The CFI
Query command can be written when the device is ready to read data or can also be written
when the part is in the product ID mode. Once in the CFI Query mode, the system can read CFI
data at the addresses given in
Table 11-5, “Common Flash Interface Definition,” on page 66
. To
exit the CFI Query mode, the product ID exit command must be given.
11.3.9
Hardware Data Protection
The Hardware Data Protection feature protects against inadvertent programs to the Flash Mem-
ory in the following ways: (a) V
CC
sense: if V
CC
is below 1.8V (typical), the program function is
inhibited. (b) V
CC
power-on delay: once V
CC
has reached the V
CC
sense level, the device will
automatically time out 10 ms (typical) before programming. (c) Program inhibit: holding any one
of OE low, CE high or WE high inhibits program cycles. (d) Program inhibit: V
PP
is less than
V
ILPP
. (e) V
PP
power-on delay: once V
PP
has reached 1.65V, program and erase operations are
inhibited for 100 ns.
11.3.10
Input Levels
While operating with a 2.65V to 3.6V power supply, the address inputs and control inputs (OE,
CE and WE) may be driven from 0 to 5.5V without adversely affecting the operation of the
device. The I/O lines can only be driven from 0 to V
CC
+ 0.6V.
Содержание AT91FR40162S
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Страница 195: ...195 6174B ATARM 07 Nov 05 AT91FR40162S Preliminary 20 5 2 CE Controlled Figure 20 15 CE Controlled...
Страница 204: ...204 6174B ATARM 07 Nov 05 AT91FR40162S Preliminary 23 AT91FR40162S Errata There is no known errata for the AT91FR40162S...