GD32F20x User Manual
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25.
External memory controller (EXMC)
25.1.
Overview
The external memory controller EXMC, is used as a translator for CPU to access a variety of
external memory, it automatically converts AMBA memory access protocol into a specific
memory access protocol defined in the configuration register, such as SRAM, ROM, NOR
Flash, PSRAM, NAND Flash, PC Card and SDRAM. Users could also tweak with the timing
parameters in the configuration register to boost up memory access efficiency. EXMC access
space is divided into multiple banks; each bank is assigned to access a specific memory type
with flexible parameter configuration as defined in the controlling register.
25.2.
Characteristics
Supported external memory:
-
SRAM
-
PSRAM/SQPI-PSRAM
-
ROM
-
NOR Flash
-
8-bit or 16-bit NAND Flash
-
16-bit PC Card
-
Synchronous DRAM(SDRAM)
Protocol translation between the AMBA and the multitude of external memory protocol
Offering a variety of programmable timing parameters to meet user’s specific needs
Each bank has its own chip-select signal which can be configured independently
Independent read/write timing configuration to a sub-set memory type
Embedded ECC hardware for NAND Flash access
8,16, or 32 bits bus width
Address and data bus multiplexing mechanism for NOR Flash and PSRAM
Write enable and byte select are provided as needed
Automatic AMBA transaction split when internal and external bus width is not compatible
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 ...
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Page 523: ...GD32F20x User Manual 523 clears AERR bit by writing 0 to it ...