GD32F20x User Manual
729
23:20
CKDIV[3:0]
Synchronous clock divide ratio. This filed is only effect in synchronous mode.
0x0: Reserved
0x1: EXMC_CLK period = 2 * HCLK period
……
0xF: EXMC_CLK period = 16 * HCLK period
19:16
Reserved
Must be kept at reset value.
15:8
WDSET[7:0]
Data setup time
This field is meaningful only in asynchronous access.
0x00: Reserved
0x01: Data setup time = 2 * HCLK period
……
0xFF: Data setup time = 256 * HCLK period
7:4
WAHLD[3:0]
Address hold time
This field is used to set the time of address hold phase, which only used in mode
D and multiplexed mode.
0x0: Reserved
0x1: Address hold time = 2 * HCLK
……
0xF: Address hold time = 16 * HCLK
3:0
WASET[3:0]
Address setup time
This field is used to set the time of address setup phase.
Note: Meaningful only in asynchronous access of SRAM,ROM,NOR Flash
0x0: Address setup time = 1 * HCLK
0x1: Address setup time = 2 * HCLK
……
0xF: Address setup time = 16 * HCLK
25.4.2.
NAND flash/PC card controller registers
NAND flash/PC card control registers (EXMC_NPCTLx) (x=1, 2, 3)
Address offset: 0x40 + 0x20 * x, (x = 1, 2, and 3)
Reset value: 0x0000 0008
This register has to be accessed by word(32-bit)
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
ECCSZ[2:0]
ATR[3]
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ATR[2:0]
CTR[3:0]
Reserved
ECCEN
NDW[1:0]
NDTP
NDBKEN NDWTEN Reserved
rw
rw
rw
rw
rw
rw
rw
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 ...