Flexible static memory controller (FSMC)
RM0090
1556/1731
DocID018909 Rev 11
1.
DATAST in FSMC_BTRx register)
Memory asserts the WAIT signal aligned to
NOE/NWE which toggles:
2. Memory asserts the WAIT signal aligned to NEx (or NOE/NWE not toggling):
if
then
otherwise
where max_wait_assertion_time is the maximum time taken by the memory to assert
the WAIT signal once NEx/NOE/NWE is low.
show the number of HCLK clock cycles that are added to the
memory access after WAIT is released by the asynchronous memory (independently of the
above cases).
Figure 447. Asynchronous wait during a read access
1. NWAIT polarity depends on WAITPOL bit setting in FSMC_BCRx register.
DATAST
4
HCLK
×
(
)
max_wait_assertion_time
+
≥
max_wait_assertion_time
address_phase
hold_phase
+
>
DATAST
4
HCLK
×
(
)
max_wait_assertion_time
address_phase
–
hold_phase
–
(
)
+
≥
DATAST
4
HCLK
×
≥
!;=
./%
(#,+
-EMORYTRANSACTION
.7!)4
$;=
.%X
DATADRIVEN
BYMEMORY
ADDRESSPHASE
DONTCARE
DATASETUPPHASE
DONTCARE