ST STM32F412

RM0402 Rev 6 271/1163
RM0402 Flexible static memory controller (FSMC)
287
1. The memory asserts the WAIT signal aligned to NOE/NWE which toggles:
2. The 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.
Figure 46 and Figure 47 show the number of HCLK clock cycles that are added to the
memory access phase after WAIT is released by the asynchronous memory (independently
of the above cases).
Figure 46. Asynchronous wait during a read access waveforms
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×≥
A[25:0]
NOE
4HCLK
Memory transaction
D[15:0]
NEx
data driven by memory
MS30463V2
address phase
data setup phase
NWAIT
don’t care don’t care