GD32F20x User Manual
685
Figure 25-5. Diagram of bank1 common space
Data Area
Command Area
Address Area
0x70000000
0x7000
FFFF
0x70010000
0x7001
FFFF
0x70020000
0x7003
FFFF
0x70040000
0x73FF
FFFF
Address
Memory Space
EXMC Memory
Bank
Bank1
Common
Space
HADDR[17:16]
00
01
1X
HADDR [17:16] bits are used to select one of the three areas.
When HADDR [17:16] = 00, the data area is selected.
When HADDR [17:16] = 01, the command area is selected.
When HADDR [17:16] = 1X, the address area is selected.
Application software uses these three areas to access NAND Flash, their definitions are as
follows.
Address area: This area is where the NAND Flash access address should be issued by
software, the EXMC will pull the address latch enable (ALE) signal automatically in
address transfer phase. ALE is mapped to EXMC_A [17].
Command area: This area is where the NAND Flash access command should be issued
by the software, the EXMC will pull the command latch enable (CLE) signal automatically
in command transfer phase. CLE is mapped to EXMC_A [16].
Data area: This area is where the NAND Flash read/write data should be accessed.
When the EXMC is in data transfer mode, software should write the data to be
transferred to the NAND Flash in this area. When the EXMC is in data reception mode,
software should read the data from the NAND Flash by reading this area. Data access
address is incremented automatically in consecutive mode, users do not need to be
concerned with access address.
SDRAM address mapping
The HADDR [28] bit (internal AHB address line 28) is used to choose one of the two memory
banks as shown in
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 ...