GD32F20x User Manual
708
NAND flash or PC card interface function
Table 25-17. 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
EXMC_NOE(NRE)
Output
Output enable
EXMC_NWE
Output
Write enable
EXMC_NWAIT/
EXMC_INT[x]
Input
NAND Flash ready/busy input signal to the EXMC, x=1, 2
Table 25-18. 16-bit PC card interface signal
EXMC Pin
Direction
Functional description
EXMC_A[10:0]
Output
Address bus of PC Card
EXMC_NIOS16
Input
Only for 16-bit I/O space data transmission width (Must be
shorted to GND)
EXMC_NIORD
Output
I/O space output enable
EXMC_NIOWR
Output
I/O space write enable
EXMC_NREG
Output
Register signal indicating if access is in Common space
or Attribute space
EXMC_D[15:0]
Input /Output
Bidirectional data bus
EXMC_NCE3_x
Output
Chip select(x=0,1)
EXMC_NOE
Output
Output enable
EXMC_NWE
Output
Write enable
EXMC_NWAIT
Input
PC Card wait input signal to the EXMC
EXMC_INTR
Input
PC Card interrupt input signal
EXMC_CD
Input
PC Card presence detection. Active high.
Supported memory access mode
Table 25-19. Bank1/2/3 of EXMC support the memory and access mode
Memory
Mode
R/W
AHB transaction size
Comments
8-bit
NAND
Async
R
8
Async
W
8
Async
R
16
Automatically split into 2 EXMC
accesses
Async
W
16
Async
R
32
Automatically split into 4 EXMC
accesses
Async
W
32
16-bit
NAND/PC Card
Async
R
8
Async
W
8
Not support this operation
Async
R
16
Summary of Contents for GD32F20 Series
Page 191: ...GD32F20x User Manual 191 Bits Fields Descriptions 31 0 TRNDATA 31 0 32 Bit Random data ...
Page 290: ...GD32F20x User Manual 290 conversion is ongoing ...
Page 325: ...GD32F20x User Manual 325 15 0 ALRM 15 0 RTC alarm value low ...
Page 385: ...GD32F20x User Manual 385 ...
Page 523: ...GD32F20x User Manual 523 clears AERR bit by writing 0 to it ...