GD32VF103 User Manual
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Table 19-6. Multiplex mode related registers configuration
EXMC_SNCTLx
Bit Position
Bit Name
Reference Setting Value
31-16
Reserved
0x0000
15
ASYNCWAIT
Depends on memory
14
Reserved
0x0
13
NRWTEN
0x0
12
WREN
Depends on memory
11:10
Reserved
0x0
9
NRWTPOL
Meaningful only when the bit 15 is set to 1
8-7
Reserved
0x1
6
NREN
0x1
5-4
NRW
Depends on memory
3-2
NRTP
0x2:NOR Flash
1
NRMUX
0x1
0
NRBKEN
0x1
EXMC_SNTCFGx
31-20
Reserved
0x0
19-16
BUSLAT
Minimum time between EXMC_NE[0] rising edge
to EXMC_NE[0] falling edge
15-8
DSET
Depends on memory and user
7-4
AHLD
Depends on memory and user
3-0
ASET
Depends on memory and user
Wait timing of asynchronous communication
Wait feature is controlled by the bit ASYNCWAIT in register EXMC_SNCTLx. During extern
memory access, data setup phase will be automatically extended by the active
EXMC_NWAIT signal if ASYNCWAIT bit is set. The extend time is calculated as follows:
I
f memory wait signal is aligned to EXMC_NOE/ EXMC_NWE:
𝑇
𝐷𝐴𝑇𝐴_𝑆𝐸𝑇𝑈𝑃
≥ 𝑚𝑎𝑥𝑇
𝑊𝐴𝐼𝑇_𝐴𝑆𝑆𝐸𝑅𝑇𝐼𝑂𝑁
+ 4𝐻𝐶𝐿𝐾
If memory wait signal is aligned to EXMC_NE:
If
𝑚𝑎𝑥𝑇
𝑊𝐴𝐼𝑇_𝐴𝑆𝑆𝐸𝑅𝑇𝐼𝑂𝑁
≥ 𝑇
𝐴𝐷𝐷𝑅𝐸𝑆_𝑃𝐻𝐴𝑆𝐸
+ 𝑇
𝐻𝑂𝐿𝐷_𝑃𝐻𝐴𝑆𝐸
𝑇
𝐷𝐴𝑇𝐴_𝑆𝐸𝑇𝑈𝑃
≥ (𝑚𝑎𝑥𝑇
𝑊𝐴𝐼𝑇_𝐴𝑆𝑆𝐸𝑅𝑇𝐼𝑂𝑁
− 𝑇
𝐴𝐷𝐷𝑅𝐸𝑆_𝑃𝐻𝐴𝑆𝐸
− 𝑇
𝐻𝑂𝐿𝐷_𝑃𝐻𝐴𝑆𝐸
) + 4𝐻𝐶𝐿𝐾
Otherwise
𝑇
𝐷𝐴𝑇𝐴_𝑆𝐸𝑇𝑈𝑃
≥ 4𝐻𝐶𝐿𝐾