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AT32F435/437
Series Reference Manual
2022.11.11
Page 515
Rev 2.03
Figure 24-8
NOR/PSRAM mode A write access
XMC_NE[x]
XMC_NOE
XMC_NWE
XMC_D[15
:
0]
1
HCLK
Data from XMC
1
HCLK
DTST+1
HCLK
High
High-Z
Memory address
Don
t care
Address signals
Data signals
Chip select
signal
XMC_A[23
:
16]
XMC_A[0]
XMC_LB
XMC_UB
Mode B
As configured in Table 24-19, Table 24-20, and Table 24-21,
the XMC uses mode B to access the external
memory. The timing of read operation is shown in
The timing of write operation is shown in
Table 24-19
Mode B— SRAM/NOR Flash chip select register
Bit
Description
Configuration
Bit 31: 20
Reserved
0x0
Bit 19
MWMC: Memory write mode control
0x0
Bit 18: 16
CRPGS
:
CRAM page size
0x0
Bit 15
NWASEN: NWAIT in asynchronous
transfer enable
Configure according to memory specifications.
Bit 14
RWTD: Read-write timing different
0x1
Bit 13
NWSEN: NWAIT in synchronous
transfer enable
0x0
Bit 12
WEN: Write enable
Configure according to needs.
Bit 11
NWTCFG: NWAIT timing configuration 0x0
Bit 10
WRAPEN: Wrapped enable
0x0
Bit 9
NWPOL: NWAIT polarity
Configure according to memory specifications.
Bit 8
SYNCBEN: Synchronous burst enable 0x0
Bit 7
Reserved
0x1
Bit 6
NOREN: NOR
Flash access enable
0x1
Bit 5: 4
EXTMDBW: External memory data
bus width
Configure according to memory specifications.
Bit 3: 2
DEV: Memory device type
0x2 (NOR Flash)
Bit 1
ADMUXEN: Address/data multiplexing
enable
0x0
Bit 0
EN: Memory bank enable
0x1