Analog Devices ADSP-BF535 Blackfin, Hardware Reference Manual

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ADSP-BF535 Blackfin Processor Hardware Reference 18-33
External Bus Interface Unit
• where
CAW
is the column address width of the SDRAM, plus
2 because the SDRAM bank is 32 bits wide (2 address bits =
4 bytes).
• 16-bit SDRAM banks: page size = 2
(CAW + 1)
• where
CAW
is the column address width of the SDRAM, plus
1 because the SDRAM bank is 16 bits wide (1 address bit =
2 bytes).
Precharge Command.
The Precharge command closes a specific internal bank in the active page
or all internal banks in the page. The SDC always does a Precharge All,
closing all internal banks.
SDRAM banks.
The SDRAM banks are four regions of memory that can be configured to
be 16 MB, 32 MB, 64 MB, or 128 MB and are selected by the
SMS[3:0]
pins. Each bank can be selected to be either all 32 bits wide or all 16 bits
wide.

Do not confuse the “SDRAM internal banks” which are internal to
the SDRAM and are selected with the bank address, with the
“SDRAM banks,” or “external banks,” that are enabled by the
SMS[3:0]
pins.
SDRAM DIMMs.
Dual In-line Memory Modules, or DIMMs, are an industry-standard
SDRAM packaging option. The DIMM consists of a small, standardized
form factor board, populated with SDRAM devices on one or both sides.
DIMMs are populated with sufficient SDRAM to provide either 32-bit or
64-bit data paths, with some configurations supporting additional data
bits for parity protection.