GD32F20x User Manual
686
Figure 25-6. SDRAM address mapping
SDRAM Bank0
SDRAM Bank1
Address
Banks
HADDR[28]
Supported memory type
0
1
0xC000 0000
0xCFFF FFFF
0xD000 0000
0xDFFF FFFF
SDRAM
SDRAM
The following table shows SDRAM address mapping of a 13-bit row and an 11-bit column
configuration.
Table 25-1. SDRAM mapping
Memory width
Internal bank
Row address
Column address
Maximum memory
capacity
8-bit
HADDR[25:24]
HADDR[23:11]
HADDR[10:0]
64 Mbytes:
4 x 8K x 2K
16-bit
HADDR[26:25]
HADDR[24:12]
HADDR[11:1]
128 Mbytes:
4 x 8K x 2K x 2
32-bit
HADDR[27:26]
HADDR[25:13]
HADDR[12:2]
256 Mbytes:
4 x 8K x 2K x 4
25.3.4.
NOR/PSRAM controller
NOR/PSRAM memory controller controls bank0, which is designed to support NOR Flash,
PSRAM, SRAM, ROM and honeycomb RAM external memory. EXMC has 4 independent
chip-select signals for each of the 4 sub-banks within bank0, named NE[x] (x = 0, 1, 2, 3).
Other signals for NOR/PSRAM access are shared. Each sub-bank has its own set of
configuration register, but only sub-bank 0 support SQPI-PSRAM access, and owns its
corresponding unique register.
Note:
In asynchronous mode, all output signals of controller will change on the rise edge of internal
AHB bus clock (HCLK).
In synchronous mode, all output data of controller will change on the fall edge of extern
memory device clock (EXMC_CLK).
NOR/PSRAM memory device interface description
Table 25-2. NOR flash interface signals description
EXMC Pin
Direction
Mode
Functional description
EXMC_CLK
Output
Sync
Clock signal for sync
Non-muxed
Output
Async/Sync
Address bus signal
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