GD32F403xx User Manual
585
Bit Position
Bit Name
Reference Setting Value
EXMC_SNCTLx
15
AYSNCWAIT
0x0
14
EXMODEN
0x0
13
NRWTEN
Depends on memory
12
WREN
0x1
11
NRWTCFG
0x0(Here must be zero)
10
WRAPEN
0x0
9
NTWTPOL
Depends on memory
8
SBRSTEN
No effect
7
Reserved
0x1
6
NREN
Depends on memory
5-4
NRW
0x1
3-2
NRTP
0x1
1
NRMUX
0x1, Depends on users
0
NRBKEN
0x1
EXMC_SNTCFGx(Write)
31-30
Reserved
0x0
29-28
ASYNCMOD
0x0
27-24
DLAT
Data latency
23-20
CKDIV
The figure above: 0x1,EXMC_CLK=2HCLK
19-16
BUSLAT
Time between EXMC_NE[x] rising edge to
EXMC_NE[x] falling edge
15-8
DSET
No effect
7-4
AHLD
No effect
3-0
ASET
No effect
21.3.5.
NAND Flash or PC Card controller
EXMC has partitioned Bank1 and Bank2 as NAND Flash access f ield, bank3 as PC Card
access field. Each bank has its own set of control register f or access timing configuration. 8-
and 16-bit NAND Flash and 16-bit PC Card are supported. An ECC hardware is provided for
the NAND Flash controller to ensure the robustness of data transfer and storage.
NAND Flash or PC Card interface function
Table 21-14. 8-bit or 16-bit NAND interface signal
EXMC Pin
Direction
Functional description
EXMC_A[17]
Output
NAND Flash address latch
(
ALE
)
EXMC_A[16]
Output
NAND Flash command latch
(
CLE
)
EXMC_D[7:0]/
EXMC_D[15:0]
Input /Output
8-bit multiplexed, bidirectional address/data bus
16-bit multiplexed, bidirectional address/data bus
EXMC_NCE[x]
Output
Chip select, x = 1, 2