Analog Devices ADSP-BF535 Blackfin, Hardware Reference Manual

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SDRAM Controller (SDC)
18-76 ADSP-BF535 Blackfin Processor Hardware Reference
Precharge Command
The Precharge command is given to precharge an active internal bank.
The SDC always issues the Precharge command to all internal SDRAM
banks (this is controlled by asserting the
SA10
pin high). The Precharge
command is executed by the SDC if the address to be accessed falls in a
different page in the same external bank or before an Auto-Refresh or
Self-Refresh. A Precharge is not done if the address to be accessed falls in
an open page in another external bank or to an external bank with no page
open. For page miss reads or writes, only the external bank to be accessed
by the read or write is precharged. For Auto-Refresh and Self-Refresh, all
external SDRAM banks are precharged at one time.
Table 18-18. Pin State During SDC Commands
Command
SMS[x] SCAS SRAS SWE SCKE SA10
Precharge low high low low high high
Bank Activate low high low high high
Load Mode Reg-
ister low low low low high
Read low low high high high low
Write low low high low high low
Auto-Refresh low low low high high
Self-Refresh low low low high low
NOP low high high high high
Command
Inhibit high high high high high