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AT32F435/437
Series Reference Manual
2022.11.11
Page 508
Rev 2.03
Table 24-7 16-bit SDRAM address mapping
Row size
HADDR (AHB address line)
27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
11-bit
Reserved
Bank
[1:0]
Row[10:0]
Column[7:0]
Reserved
Bank
[1:0]
Row[10:0]
Column[8:0]
Reserved
Bank
[1:0]
Row[10:0]
Column[9:0]
Reserved
Bank
[1:0]
Row[10:0]
Column[10:0]
12-bit
Reserved
Bank
[1:0]
Row[11:0]
Column[7:0]
Reserved
Bank
[1:0]
Row[11:0]
Column[8:0]
Reserved
Bank
[1:0]
Row[11:0]
Column[9:0]
Reser
ved
Bank
[1:0]
Row[11:0]
Column[10:0]
13-bit
Reserved
Bank
[1:0]
Row[12:0]
Column[7:0]
Reserved
Bank
[1:0]
Row[12:0]
Column[8:0]
Reser
ved
Bank
[1:0]
Row[12:0]
Column[9:0]
Re
s.
Bank
[1:0]
Row[12:0]
Column[10:0]
24.4 NOR/PSRAM
NOR/PSRAM offers multiple access modes with different timings to drive multiple memories including
NOR Flash, SRAM, PSRAM and Cellular RAM.
There are two banks, bank 1 and bank, with independent control registers. Such two banks can be
accessed by means of different timings and different chip-select signals.
24.4.1 Operating mode
Pin function:
Pin signals vary from external memory to external memory. Table 24-8 lists typical pin signals.
Table 24-8
Pin signals for NOR and PSRAM
XMC pin name
NOR Flash
PSRAM
XMC_CLK
Clock (synchronous mode)
Clock (synchronous mode)
XMC_NE[x]
Chip-select
Chip-select
XMC_NADV
Address latch or address valid
Address latch or address valid
XMC_A[23:16], XMC_A[0]
Address bus
Address bus
XMC_NOE
Output enable
Output enable
XMC_NWE
Write enable
Write enable
XMC_LB, XMC_UB
Without using XMC_LB, XMC_UB
XMC_LB: lower byte
XMC_UB: upper byte
XMC_D[15: 0]
Data bus
multiplexed address data bus (multiplex
and synchronous mode)
Data bus
multiplexed address data bus (multiplex
and synchronous mode)
XMC_NWAIT
NOR Flash wait request
PSRAM wait request
Note: If the memory data size is 8 -bit, the typical data bus is XMC_D[7: 0].
Access address
The upper bytes of the HADDR bit is used to select a memory bank while the lower bytes to data memory
address. HADDR is a byte address whereas the XMC supports the memory addressed in words or half
words. Address translation between them is shown in Table 22-5. As long as read/write access to a
specific address occurs, the XMC will enable chip-select signals and write/read operation to the external
memories according to the HADDR bit.