ST STM32F405 Reference Manual page 1642

Flexible memory controller (FMC)
Bit 6 FACCEN: Flash access enable
Enables NOR Flash memory access operations.
0: Corresponding NOR Flash memory access is disabled
1: Corresponding NOR Flash memory access is enabled (default after reset)
Bits 5:4 MWID[1:0]: Memory data bus width.
Defines the external memory device width, valid for all type of memories.
00: 8 bits,
01: 16 bits (default after reset),
10: 32 bits,
11: reserved, do not use.
Bits 3:2 MTYP[1:0]: Memory type.
Defines the type of external memory attached to the corresponding memory bank:
00: SRAM (default after reset for Bank 2...4)
01: PSRAM (CRAM)
10: NOR Flash/OneNAND Flash (default after reset for Bank 1)
11: reserved
Bit 1 MUXEN: Address/data multiplexing enable bit.
When this bit is set, the address and data values are multiplexed on the data bus, valid only with
NOR and PSRAM memories:
0: Address/Data nonmultiplexed
1: Address/Data multiplexed on databus (default after reset)
Bit 0 MBKEN: Memory bank enable bit.
Enables the memory bank. After reset Bank1 is enabled, all others are disabled. Accessing a
disabled bank causes an ERROR on AHB bus.
0: Corresponding memory bank is disabled
1: Corresponding memory bank is enabled
SRAM/NOR-Flash chip-select timing registers 1..4 (FMC_BTR1..4)
Address offset: 0x04 + 8 * (x – 1), x = 1..4
Reset value: 0x0FFF FFFF
Reset value: 0x0FFF FFFF
FMC_BTRx bits are written by software to add a delay at the end of a read /write
transaction. This delay allows matching the minimum time between consecutive
transactions (t
memory to free the data bus after a read access (t
This register contains the control information of each memory bank, used for SRAMs,
PSRAM and NOR Flash memories.If the EXTMOD bit is set in the FMC_BCRx register, then
this register is partitioned for write and read access, that is, 2 registers are available: one to
configure read accesses (this register) and one to configure write accesses (FMC_BWTRx
registers).
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from NEx high to FMC_NEx low) and the maximum time required by the
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