GD32VF103 User Manual
421
Table 19-5. EXMC_timing models
Timing
model
Extend
mode
Mode description
Write timing
parameter
Read timing
parameter
Async
Mode AM
0
NOR Flash address/data mux
DSET
AHLD
ASET
BUSLAT
DSET
AHLD
ASET
BUSLAT
Table 19-5. EXMC_timing models
, EXMC NOR Flash / PSRAM controller
provides a timing model, users can modify those parameters listed in
PSRAM controller timing parameters
to satisfy different external memory type and user’s
requirements. Different timing patterns for read and write access could be generated
independently according to EXMC_SNTCFGx
register’s configuration.
Asynchronous access timing diagram
Mode AM - NOR Flash address / data bus multiplexing
Figure 19-4. Multiplex mode read access
1 HCLK
Address
(EXMC_A[25:16])
Address Valid
(EXMC_NADV)
Chip Enable
(EXMC_NEx)
Output Enable
(EXMC_NOE)
Write Enable
(EXMC_NWE)
Data Mux
(EXMC_D[15:0])
Memory Output
Address Setup Time
(ASET+1 HCLK)
Data Setup Time
(DSET+1 HCLK)
Address Hold Time
(AHLD+1 HCLK)
Address[15:0]
Address[25:16]
2 HCLK
Figure 19-5. Multiplex mode write access
Address
(EXMC_A[25:16])
Address Valid
(EXMC_NADV)
Chip Enable
(EXMC_NEx)
Output Enable
(EXMC_NOE)
Write Enable
(EXMC_NWE)
Data
(EXMC_D[15:0])
Address Setup Time
(ASET+1 HCLK)
Data Setup Time
(DSET+1 HCLK)
1 HCLK
Address Hold Time
(AHLD HCLK)
Address[15:0]
Address[25:16]
EXMC output