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SMC memory block
Storage space
Start address
End address
Memory block 3-NAND
flash memory
General
0x80000000
0x83FFFFFF
Attributes
0x88000000
0x8BFFFFFF
Memory block 4-PC
card
General
0x90000000
0x93FFFFFF
Attributes
0x98000000
0x9BFFFFFF
I/O
0x9C000000
0x9FFFFFFF
NAND flash memory block is divided into three blocks in part of the low-byte
area, and different blocks can be accessed through HADDR [17:16]. The
specific division and selection of these three blocks are shown in the table
below:
Table 22 NAND Memory Block Division
HADDR[17:16]
Address range
Block name
00
0x000000-0x00FFFF
Data block
01
0x010000-0x01FFFF
Command block
1X
0x020000-0x03FFFF
Address
In order to read and write NAND memory normally, the following steps are
needed:
Transmit command to the memory
Transmit the address for reading and writing to the memory
Read/Write data
The operation address of the corresponding three-step operation corresponds
to the three blocks in the memory block. To transmit a command to the memory
is to write the corresponding command value to the command block; to transmit
an address to the memory is to transmit the corresponding address value to the
address block; to read and write data is to read and write in the data block;
finally write or read out the internal unit of NAND, and the address of the
corresponding unit is the address written in the address block.
Interface signal and controller
NAND/PC card controller can control three memory blocks. The memory blocks
2 and 3 support NAND Flash, and the memory block 4 supports PC card
devices. Three memory blocks have their own chip selection signals, and the
specific interfaces and functions are as follows:
Table 23 NAND Flash Interface Signal
SMC signal name
Signal direction
Function
NCE[x]
Output
Chip selection signal, x=2, 3
NOE
(
=NRE
)
Output
Read enable signal