Flexible static memory controller (FSMC)
RM0090
1538/1731
DocID018909 Rev 11
PSRAM memories are addressed in 16-bit words. The maximum capacity is 512
Mbit (26
address lines).
36.5.2
Supported memories and transactions
below displays an example of the supported devices, access modes and
transactions when the memory data bus is 16-bit for NOR, PSRAM and SRAM.
Transactions not allowed (or not supported) by the FSMC in this example appear in gray.
AD[15:0] I/O
16-bit
multiplexed, bidirectional address/data bus
NE[x]
O
Chip select, x = 1..4 (called NCE by PSRAM (Cellular RAM i.e. CRAM))
NOE
O Output
enable
NWE
O Write
enable
NL(= NADV)
O
Address valid PSRAM input (memory signal name: NADV)
NWAIT
I
PSRAM wait input signal to the FSMC
NBL[1]
O
Upper byte enable (memory signal name: NUB)
NBL[0]
O
Lowed byte enable (memory signal name: NLB)
Table 219. Multiplexed I/O PSRAM (continued)
FSMC signal name
I/O
Function
Table 220. NOR Flash/PSRAM controller: example of supported memories
and transactions
Device
Mode
R/W
AHB
data
size
Memory
data size
Allowed/
not
allowed
Comments
NOR Flash
(muxed I/Os
and nonmuxed
I/Os)
Asynchronous R 8
16
Y
Asynchronous W
8
16
N
Asynchronous R 16
16
Y
Asynchronous W 16
16
Y
Asynchronous R
32
16
Y
Split into 2 FSMC accesses
Asynchronous W
32
16
Y
Split into 2 FSMC accesses
Asynchronous
page
R
-
16
N
Mode is not supported
Synchronous R
8
16
N
Synchronous R 16
16
Y
Synchronous R 32
16
Y